The Good
Yu Yu Hakusho's intros and endings are great, so are Dragonball's.
I've enjoyed all of Pokemon's intros except for Orange Islands.
Ultimate Muscle's intro was pretty funny.
Baki the Grappler's intro is completely awesome, but it isn't exactly an english intro, just an all new intro for the english release because the old one had liscense issues.
Digimon Frontier's intro was good.
Rurouni Kenshin's english version rules all, I've walked down the street singing it before.
Berserk's Forces is a great song. I also like the opening and ending.
Shaman King is a good song for the intro, but not great. I think the same for Tokyo Me… er, Mew Mew Power's intro. Both can be catchy, though.
Would Naruto's Wind count as an english ending?
The Bad
DBZ and GT. Rock the Dragon, Step into the Grand Tour, and the electric guitar intros are insults to my ears. The Newest one isn't as bad, but it is LONG.
Yugioh, just a very dorky opening.
One Piece, it's an real bad rap song, but I do laugh at some of it's lines.
Card Captors, horrible dub opening for a horridly dubbed show. I'd wish they'd go back and dub it in full entirety with good voices. It would definately sell.
Digimon Adventure 01, 02, and Tamers had boring songs. Very repetitious.
Pokemon Orange Islands, you wanna be a Masta!. Just sad.
Well, that's all the ones I can think of on either side of the spectrum.