There's lots of stuff I enjoyed watching. I don't really think I have a favourite.

Kaleido Star
Full Metal Alchemist
Full Moon Wo Sagash-ite (- cause I can't type the word~)
Mai HiME
.Hack//sign
Escaflowne
Gundam Seed

And probably missing a lot. I'm currently watching

Mai Otome
Jigoku Shoujo
Fate/Stay night

I think Mai Otome is my favourite out of the three.