Just in case you're considering Tsubasa, I would definitely suggest reading the manga rather than watching the anime. The anime, while sort of pretty, is actually a really poor adaptation and the characters are sort of OOC (i.e. they "straighten out" Fay, have Kuro make inappropriate flirt-noises at Sakura, etc.). It's really fucking weird. XD HOWEVER, when you get to the later chapters of the manga, there's a really excellent OVA adaptation that was done by a different studio that's five episodes long if you want to watch those to get the look of it moving and the sound of the voices and stuff. There's also a movie too, but I think that one is harder to find online.