Found this incredibly interesting:
Someone on GameFAQs (kirbydude385) mathmatically ranked each typing and combination of typings from best to worst Offensively, Defensively and Overall.
Defensively:
! Steel/Fairy: 13.25
Flying/Steel: 13.50
Ghost/Steel: 14.25
Steel/Dragon: 14.25
Water/Steel: 14.50
Normal/Ghost: 15.00
Steel: 15.00
Fighting/Steel: 15.50
Ghost/Dark: 15.50
Bug/Steel: 15.75
Poison/Steel: 15.75
Ground/Steel: 15.75
Normal/Steel: 16.00
Water/Ground: 16.00
Electric/Steel: 16.00
Poison/Dark: 16.00
Fire/Steel: 16.25
Grass/Steel: 16.25
Psychic/Steel: 16.25
Ghost/Fairy: 16.25
Electric/Flying: 16.50
Electric/Ghost: 16.50
Electric/Fairy: 16.50
Dark/Steel: 16.50
Normal/Poison: 17.00
Normal/Fairy: 17.00
Water: 17.00
Water/Poison: 17.00
Water/Ghost: 17.00
Water/Fairy: 17.00
Poison/Fairy: 17.00
Ghost: 17.00
Fire/Ghost: 17.25
Fire/Fairy: 17.25
Fighting/Ghost: 17.25
Normal/Electric: 17.50
Electric: 17.50
Poison: 17.50
Poison/Ghost: 17.50
Dragon/Fairy: 17.50
Fairy: 17.50
Fire/Water: 17.75
Fire/Fighting: 17.75
Water/Electric: 17.75
Flying/Poison: 17.75
Dark/Fairy: 17.75
Normal: 18.00
Normal/Fire: 18.00
Normal/Water: 18.00
Normal/Flying: 18.00
Fire: 18.00
Fire/Dark: 18.00
Fire/Dragon: 18.00
Water/Dragon: 18.00
Electric/Bug: 18.00
Electric/Poison: 18.00
Ghost/Dragon: 18.00
Ground/Fairy: 18.00
Flying/Ghost: 18.25
Poison/Ground: 18.25
Poison/Dragon: 18.25
Ghost/Ground: 18.25
Normal/Psychic: 18.50
Fire/Flying: 18.50
Fire/Ground: 18.50
Water/Bug: 18.50
Water/Flying: 18.50
Electric/Fighting: 18.50
Electric/Dark: 18.50
Flying: 18.50
Flying/Dark: 18.50
Flying/Ground: 18.50
Flying/Fairy: 18.50
Fire/Grass: 18.75
Fire/Electric: 18.75
Electric/Dragon: 18.75
Poison/Psychic: 18.75
Psychic/Fairy: 18.75
Normal/Bug: 19.00
Normal/Ground: 19.00
Normal/Dragon: 19.00
Water/Dark: 19.00
Grass/Ghost: 19.00
Electric/Ground: 19.00
Bug/Poison: 19.00
Bug/Ghost: 19.00
Dark: 19.00
Ground: 19.00
Dragon: 19.00
Fire/Poison: 19.25
Water/Grass: 19.25
Grass/Poison: 19.25
Fighting/Dark: 19.25
Bug/Fairy: 19.25
Normal/Fighting: 19.50
Fire/Psychic: 19.50
Water/Fighting: 19.50
Electric/Psychic: 19.50
Ice/Ghost: 19.50
Fighting: 19.50
Fighting/Fairy: 19.50
Flying/Rock: 19.50
Bug: 19.50
Rock/Steel: 19.50
Fire/Bug: 19.75
Grass/Electric: 19.75
Ice/Steel: 19.75
Fighting/Flying: 19.75
Fighting/Poison: 19.75
Ghost/Rock: 19.75
Water/Psychic: 20.00
Fighting/Psychic: 20.00
Bug/Dark: 20.00
Bug/Rock: 20.00
Psychic: 20.00
Dark/Ground: 20.00
Flying/Psychic: 20.25
Flying/Dragon: 20.25
Bug/Dragon: 20.25
Normal/Dark: 20.50
Electric/Ice: 20.50
Ice/Poison: 20.50
Bug/Ground: 20.50
Rock/Fairy: 20.50
Ground/Dragon: 20.50
Water/Ice: 20.75
Fighting/Ground: 20.75
Poison/Rock: 20.75
Normal/Grass: 21.00
Grass: 21.00
Grass/Rock: 21.00
Grass/Fairy: 21.00
Psychic/Ghost: 21.00
Psychic/Dark: 21.00
Psychic/Ground: 21.00
Psychic/Dragon: 21.00
Dark/Dragon: 21.00
Rock: 21.00
Water/Rock: 21.25
Electric/Rock: 21.25
Rock/Dragon: 21.25
Ice: 21.50
Ice/Ground: 21.50
Ice/Dragon: 21.50
Ice/Fairy: 21.50
Fighting/Bug: 21.50
Fighting/Dragon: 21.50
Fire/Ice: 21.75
Bug/Psychic: 21.75
Normal/Rock: 22.00
Grass/Ground: 22.00
Ice/Flying: 22.00
Fighting/Rock: 22.00
Flying/Bug: 22.00
Fire/Rock: 22.25
Grass/Flying: 22.25
Normal/Ice: 22.50
Ice/Fighting: 22.50
Psychic/Rock: 22.50
Grass/Fighting: 23.00
Grass/Dark: 23.00
Ice/Psychic: 23.00
Dark/Rock: 23.00
Grass/Dragon: 23.25
Ice/Dark: 23.50
Grass/Psychic: 24.00
Rock/Ground: 24.25
Ice/Bug: 24.50
Grass/Ice: 25.00
Grass/Bug: 25.00
Ice/Rock: 26.00
! The Higher the Number the Worst Defensively.
! It might be worth explaining what these numbers actually mean. 0.25 is a double resistance, 0.5 is a single resistance, 1 is normal damage, 2 is a single weakness, 4 is a double weakness. Add up all 18 types and you get that number. A theoretical typeless Pokemon would have a weakness total of 18.
Offensively:
! Here are my results:
1. Ice/Ground: 311.00
2. Rock/Ground: 306.00
3. Fire/Ground: 303.00
4. Flying/Ground: 300.50
5. Ground/Fairy: 296.50
6. Fighting/Rock: 290.50
7. Ice/Fighting: 287.50
8. Ground/Steel: 285.00
9. Fighting/Ground: 283.00
10. Fighting/Flying: 279.50
11. Ice/Rock: 279.00
12. Bug/Ground: 277.50
13. Poison/Ground: 277.00
14. Fire/Fighting: 276.00
15. Ghost/Ground: 275.50
16. Electric/Ground: 273.50
17. Fighting/Ghost: 273.00
17. Rock/Fairy: 273.00
19. Dark/Ground: 272.50
20. Fire/Rock: 272.00
21. Fire/Ice: 270.75
22. Fire/Fairy: 268.50
23. Psychic/Ground: 268.00
24. Fire/Water: 267.25
25. Water/Rock: 267.00
26. Water/Ground: 266.00
27. Fighting/Dark: 265.00
28. Fighting/Fairy: 264.50
28. Ground/Dragon: 264.50
30. Grass/Rock: 264.00
31. Water/Fighting: 263.00
32. Water/Ice: 262.00
32. Fighting/Psychic: 262.00
32. Flying/Rock: 262.00
35. Water/Flying: 261.00
35. Water/Fairy: 261.00
35. Fighting/Steel: 261.00
38. Grass/Ground: 260.25
39. Ghost/Rock: 259.00
40. Rock/Steel: 258.00
41. Fire/Grass: 257.25
42. Psychic/Rock: 256.50
43. Bug/Rock: 254.75
44. Ice/Steel: 254.25
45. Fire/Psychic: 254.00
45. Fire/Ghost: 254.00
45. Electric/Fighting: 254.00
45. Ice/Flying: 254.00
45. Ice/Ghost: 254.00
50. Normal/Ground: 253.00
51. Dark/Rock: 252.00
52. Fire/Steel: 251.75
53. Fire/Electric: 250.50
53. Electric/Ice: 250.50
53. Ice/Dark: 250.50
56. Fire/Dark: 250.00
57. Ice/Fairy: 249.75
58. Fighting/Poison: 249.25
59. Grass/Ice: 247.75
60. Fire/Flying: 247.00
60. Fire/Dragon: 247.00
60. Ice/Psychic: 247.00
63. Ghost/Fairy: 246.50
64. Flying/Steel: 246.25
65. Dark/Fairy: 245.50
66. Water/Bug: 245.00
66. Grass/Flying: 245.00
68. Fighting/Dragon: 244.50
69. Fire/Bug: 243.50
70. Water/Ghost: 243.00
70. Flying/Ghost: 243.00
70. Flying/Dark: 243.00
73. Grass/Fighting: 242.25
74. Steel/Fairy: 241.75
75. Water/Poison: 241.50
75. Water/Steel: 241.50
75. Flying/Fairy: 241.50
75. Poison/Rock: 241.50
75. Rock/Dragon: 241.50
80. Ice/Bug: 240.75
81. Electric/Rock: 240.50
82. Fighting/Bug: 240.25
83. Water/Psychic: 239.50
83. Water/Dark: 239.50
83. Electric/Fairy: 239.50
83. Ghost/Steel: 239.50
87. Dark/Steel: 239.00
88. Fire/Poison: 237.00
89. Ice/Poison: 235.75
90. Electric/Flying: 235.50
91. Water/Electric: 233.25
92. Water/Dragon: 232.50
92. Flying/Bug: 232.50
94. Electric/Steel: 232.00
95. Grass/Fairy: 231.75
96. Bug/Psychic: 231.50
96. Psychic/Steel: 231.50
98. Psychic/Fairy: 229.50
99. Bug/Steel: 228.25
100. Normal/Rock: 228.00
100. Ice/Dragon: 228.00
102. Grass/Ghost: 227.00
103. Bug/Ghost: 226.50
104. Ground: 226.25
105. Flying/Psychic: 226.00
106. Grass/Steel: 225.75
107. Electric/Bug: 224.50
107. Electric/Ghost: 224.50
107. Poison/Fairy: 224.50
110. Normal/Fire: 224.00
110. Flying/Dragon: 224.00
110. Poison/Ghost: 224.00
113. Poison/Dark: 223.50
113. Psychic/Ghost: 223.50
115. Bug/Fairy: 223.25
116. Normal/Ice: 223.00
116. Grass/Psychic: 223.00
116. Psychic/Dark: 223.00
116. Steel/Dragon: 223.00
120. Grass/Dark: 221.50
121. Electric/Dark: 221.00
122. Electric/Psychic: 220.50
123. Water/Grass: 220.25
124. Poison/Steel: 219.25
125. Rock: 216.75
126. Normal/Water: 216.00
126. Grass/Poison: 216.00
126. Flying/Poison: 216.00
129. Ghost/Dragon: 215.50
130. Poison/Psychic: 214.75
131. Bug/Dark: 214.25
132. Grass/Dragon: 213.00
133. Dragon/Fairy: 212.50
134. Electric/Dragon: 212.00
135. Grass/Bug: 211.50
136. Grass/Electric: 211.25
137. Electric/Poison: 210.75
138. Normal/Fairy: 209.50
139. Normal/Steel: 207.00
139. Ice: 207.00
139. Psychic/Dragon: 207.00
142. Fire: 206.50
142. Dark/Dragon: 206.50
144. Bug/Dragon: 204.50
145. Poison/Dragon: 204.00
146. Normal/Flying: 203.75
147. Normal/Ghost: 201.00
148. Bug/Poison: 200.25
149. Normal/Dark: 199.00
150. Water: 197.25
150. Flying: 197.25
150. Fairy: 197.25
153. Ghost/Dark: 197.00
154. Normal/Grass: 196.50
155. Normal/Fighting: 195.50
155. Fighting: 195.50
157. Normal/Electric: 193.50
158. Normal/Psychic: 191.50
159. Normal/Bug: 188.50
160. Steel: 187.50
161. Dark: 178.75
162. Ghost: 178.50
163. Normal/Dragon: 177.00
164. Normal/Poison: 173.00
165. Psychic: 169.25
166. Dragon: 161.00
167. Electric: 160.25
168. Grass: 159.75
168. Bug: 159.75
170. Poison: 151.50
171. Normal: 136.25
! > Here's what I did:
1. Recreated the type chart on Excel with all 18 types attacking all 171 type combinations: http://i.imgur.com/ZXqPmFY.jpg
2. For every type combination, I summed all the numbers that were greater. For example, this is the start of the summation for Fire/Water: http://i.imgur.com/aD6wQvy.jpg
The higher the number, the better that type combination is offensively.
Now OF COURSE this does not automatically judge a Pokemon's offensive powers. This tactic does not take into account a Pokemon's stats or ability. It also doesn't take into account defensive abilities like Levitate or the power of moves (The strongest Fighting move is stronger than the strongest Dark move for example). So take this with a grain of salt, but I found it interesting nonetheless, and number 1 wasn't what I expected
Overall:
! Alright done with overall rankings. The numbers are just the sum of the offensive and defensive place.
! 18. Ground/Steel
39. Water/Ground
43. Fighting/Steel
50. Fighting/Ghost
52. Ground/Fairy
55. Fire/Fairy
56. Fire/Fighting
60. Water/Fairy
66. Fire/Water
66. Fire/Ground
66. Flying/Steel
67. Flying/Ground
69. Fire/Steel
72. Poison/Ground
74. Ghost/Ground
75. Steel/Fairy
78. Fire/Ghost
80. Water/Steel
85. Electric/Ground
86. Ghost/Steel
90. Ghost/Fairy
95. Water/Ghost
98. Water/Flying
100. Water/Poison
103. Fire/Dark
104. Electric/Fairy
107. Fire/Dragon
107. Electric/Steel
107. Dark/Fairy
108. Electric/Fighting
108. Dark/Steel
109. Bug/Steel
111. Electric/Flying
113. Psychic/Steel
115. Fire/Grass
115. Fighting/Flying
117. Fighting/Dark
119. Steel/Dragon
123. Fire/Flying
123. Grass/Steel
123. Fighting/Fairy
126. Water/Fighting
126. Poison/Dark
127. Fire/Electric
127. Flying/Rock
128. Electric/Ghost
129. Normal/Ground
129. Water/Bug
129. Flying/Ghost
130. Dark/Ground
132. Bug/Ground
132. Poison/Fairy
133. Water/Electric
133. Flying/Dark
134. Poison/Steel
135. Fighting/Ground
135. Rock/Steel
137. Rock/Fairy
138. Flying/Fairy
139. Water/Dragon
140. Fire/Psychic
140. Ice/Ghost
143. Ice/Ground
143. Fighting/Psychic
144. Ghost/Rock
146. Poison/Ghost
148. Ground/Dragon
149. Ice/Steel
152. Normal/Steel
152. Psychic/Ground
153. Normal/Ghost
154. Electric/Bug
154. Bug/Rock
156. Fighting/Rock
157. Normal/Fire
158. Water/Ice
159. Grass/Rock
161. Ghost/Dark
162. Water/Dark
163. Normal/Fairy
163. Fighting/Poison
164. Water/Rock
164. Ice/Fighting
166. Steel
168. Flying/Poison
169. Fire/Ice
169. Rock/Ground
169. Dragon/Fairy
172. Psychic/Fairy
173. Normal/Water
173. Electric/Ice
174. Fire/Bug
175. Fire/Rock
175. Water
176. Ghost/Dragon
178. Fire/Poison
181. Grass/Ghost
182. Ice/Rock
182. Bug/Ghost
183. Ground
184. Electric/Poison
184. Electric/Dark
186. Fairy
187. Ghost
188. Grass/Ground
189. Normal/Poison
189. Fire
193. Normal/Electric
193. Normal/Flying
194. Water/Psychic
195. Ice/Flying
199. Ice/Fairy
199. Psychic/Rock
201. Poison/Rock
203. Electric
204. Poison/Psychic
204. Poison/Dragon
205. Bug/Fairy
206. Poison
208. Electric/Dragon
209. Ice/Poison
210. Fighting/Dragon
211. Dark/Rock
213. Water/Grass
213. Flying
214. Rock/Dragon
216. Grass/Poison
217. Electric/Psychic
218. Normal
218. Ice/Dark
220. Electric/Rock
220. Ice/Psychic
221. Normal/Psychic
222. Flying/Psychic
224. Grass/Fairy
224. Fighting/Bug
226. Grass/Flying
227. Flying/Dragon
227. Bug/Poison
228. Grass/Ice
233. Grass/Fighting
238. Normal/Bug
240. Dark
241. Grass/Electric
242. Normal/Dragon
242. Ice/Dragon
242. Bug/Dark
242. Psychic/Ghost
244. Bug/Psychic
245. Psychic/Dark
245. Dragon
248. Ice/Bug
250. Normal/Fighting
250. Normal/Rock
250. Fighting
254. Rock
261. Bug/Dragon
262. Flying/Bug
263. Bug
268. Psychic/Dragon
269. Normal/Dark
271. Dark/Dragon
273. Normal/Ice
276. Psychic
280. Grass/Dark
281. Ice
282. Grass/Psychic
283. Normal/Grass
296. Grass/Dragon
297. Grass
304. Grass/Bug
Threads: http://www.gamefaqs.com/boards/696959-pokemon-x/68643088
http://www.gamefaqs.com/boards/696959-pokemon-x/68478134