They need to be in the wdas canon, so no direct to video sequels, pixar, or stuff like 'mars needs moms'.
Oh and give an explanation, brief or long as to why you chose that movie.
For number 1 I will go with 'the lion king'. As for why, many here will agree that almost everything about it is excellent. There are a few holes that are never explained, like who is nalas father or stuff like simba and nalas romance feeling a bit rushed. Those things are minor issues to me.
Number 2 is Aladdin. The soundtrack is great, aladdin is probably the most charismatic disney male lead and the genie is hilarious. It doesn't hit the same highs as 'the lion king' but it's still a very worthy movie.
Number 3 is tarzan. Like the above two, great soundtrack. It's an all around solid film that has very few lows... To me at least.
Number 4 was a harder choice but I went with 'the emporers new groove'. As a comedy it's great. It might just be the funniest disney animated film.
Number 5 is Fantasia. Like 1-3 it has a great soundtrack but it's just using classical and ballet music and creating animated stories around it. It is my favorite walt era disney film.
Outside of Tangled I haven't been super impressed by the current era of cgi disney films but i'm hoping that zootopia changes that a little.