I've been watching a few of my early 1990s Disney films on VHS pending getting rid of them to divest my VHS stock and I'm really digging it and it made me think to do this poll, given all the acclaim of Pixar lately.
I am probably a little biased because the Disney run was smack dab in my childhood so I am nostalgic, and because I'm a musicals kind of guy, but for me it is Disney and not really even close. Those are six solid films drawing on interesting, classic-seeming stories with just tremendous songs. Having not watched most of these in years there are a surprising number of the jokes that are aimed at parents as well.
While Finding Nemo is certainly up there alongside my favorite Disney films of this era and The Incredibles would be competitive with most of them too; the other four kind of make me shrug ultimately. I like them well enough but they don't have that special feeling of the Disneys.
BTW, for me it is Aladdin, Lion King, Nemo, Hunchback, Beauty, Incredibles, Pocahontas, Up, Wall-E, Mermaid, Cars, Ratatouille.