The Lion King-I know it's the obvious choice, but I find this to be one of the greatest movies of all time animated or otherwise.(personally, I hate the segregation that animated films get from live action and almost see the best animated film category for the oscars as an insult and way of saying, "they'll never be best picture worthy). Everything about this movie is amazing from the songs and characters, to the plot and animation. It's a real treat and I think it's enjoyable for anyone of any age.
Curious George-The animation in this film is just so fun to watch and it's a real nice story. Im not saying it's definitively aweseme as far as animated movies go, but this is just something you should treat yourself to at least once. but this is also one of the only movies I love that seems almost exclusively for children and is not fit for everyone above the age of 3.
Whisper of the Heart-One of the most outstanding and inpspiring films I've ever seen. This is more proof that an animated movie doesn't have to be completely unrealistic and childish. With the exception of a sequence or two, this may have been live action, but I don't know if it would have been as effective. who knows, and it really doesn't matter. The themes and characters in this movie are so real and I think it's one of the most re-watchable of all the Ghibli films available. (I just decided to name this one, but Ghibli has never produced one bad movie in my opinion, but came close with Kiki's Delivery Service.)
Beauty and the Beast-I watched this movie for the first time in roughly 10 years, and was equally as amazed as I was when I was a kid. The animation seemed so much ahead of it's time and I forgot how dramatic the story seemed and I loved every minute of it. In my opinion, arguably the 2nd best disney feature ever.
As I close this post, I forgot to keep it to only American but I'll just keep that in mind for next time

, in case no one here has seen it...because it's an essential. I'll probably add more in the future and heck maybe I'll reach 50.(highly doubt it)