Oh my freakin' gosh...
The Lion King 1 and 2 soundtracks... That's right, the whole things. I love all of the songs equally... Well, except Hakuna Matata and Be Prepared. Both are just sheer awesomeness. XD
Tarzan... Oh wow... I can't pick one song out of it that I like more. You'll be in my Heart is awesome, but... Oh crap, why can't I remember that rockin' ape song?! That was awesome! Shame I can't remember its name...
Tale as Old as Time? Oh heckz yeah. Love it.
Friend Like Me from Alladin is just pure MONEY right there. Robin Williams at his finest.
Part of Your World and Under the Sea from The Little Mermaid.
Make a Man Out of You and Reflection from Mulan... Yeah, no explanation needed there. XD
Bear Necessities from the Jungle Book...
Supercalifragilisticexpialidocius from Mary Poppins...
Not EXACTLY Disney, but it is from Touchstone, which is owned by Disney. The Nightmare Before Christmas Soundtrack. Whole freakin' thing.
Hmm... There are others, but I'll just stop here for now. :)