What is your favorite animated movie?

And more importantly, why? Do you prefer any studio/company/etc. over any other? Disney? DreamWorks? Pixar? Warner Brothers?

I’ve always had a fondness for the Wallace & Grommit series, which was played very frequently on Cartoon Network when I was younger. Curse of the Were-Rabbit was a great movie, but I still love the original shorts too. I also watched The Iron Giant for the first time in years, and I completely forgot how awesome it was.