One Piece
Zoro vs Mr. 1…. that entire fight was just awesome...in so many ways
Dvorak's New World symphony playing during the Luffy vs Crocodile fight was just amazingly done...
Most of Robin's past.... I was teary-eyed watching Saul sacrifice himself for poor little Robin....
When Robin finally accepted the help of her nakama... I always love that scene in the manga especially... Though, I was so happy at how well it was done in the anime....
Afro Luffy.... just re-watched the Davey Back episodes... oh man those are great... except the fillers, those were ok....
Groggy Ring... mainly cuz Zoro and Sanji kicked a lot of ass in this match, even after getting the shit beat outta them. And I love how Zoro still fights without his swords (Swordless Tatsumaki~~! sooo hot.)
! The Straw Hats saying goodbye to Going Merry… I still can't believe she's gone.... She is just a ship but dammit.... I was crying just as much as Nami was when I first read that chapter.... It was such a sad and beautiful moment....Ok, better stop before I start crying again....
! aaand of course, finding out who Luffy's dad and granddad are... that was pretty amazing... the return of Coby and Helmeppo.... New World....
Smoker's most awesome line "Tell them to go eat shit! This is real justice!"
Luffy beating the shit outta Bellamy… oh man... so much awesome. One Punch.
Zoro catching Robin.... my inner fangirl squeals with joy everytime I see this scene....
Pretty much any scene where Zoro and Sanji argue... it just makes me smile and think of how funny it is that they are paired up so often XD
I'm sure there are more, but I'll stop for now ^^
Rurouni Kenshin/Samurai X
At around the beginning of the OVA, when Hiko says that line "You won't be alive long enough to remember my name…" and proceeds to slice up some poor guy in three piece in an instant.... My jaw dropped when I first saw that
Kenshin vs Saito... I almost thought this fight was more exciting than any of the other boss fights. It was animated really well too
Dragon Ball
Trunks destroying the Androids in his future time… That was really awesome
Vegeta and Trunks coming out of the Room of Spirit and Time... mainly because Trunks looked freakin' HOT with the long hair XDDD
Gohan levelling up to SSJ2 in the Japanese version, because it wasn't as cool in the dub.