FMA? As in the original? Because I strongly disliked the English FMA.. eck.
Hmmm, I heard FLCL was better in English. TTGL is tolerable, for the most part, to me in English, though if I have any choice whatsoever I'd still prefer Japanese. .hack//sign was pretty good in English, don't know if I saw much of the Japanese though. As far as I can tell, I like both versions of InuYasha, though I don't know if I have a preference. Digimon, at least the original, is pretty good in English :]
I can maybe think of a few characters that are better in English, but a whole series is rare.. since American girls try to do the cutesy Asian voice and end up sounding like either ******* or *******. That and the English language is kinda gross to listen to. I'll edit if I think of anything.