As a kid I remember watching Fantasia and being entranced with the concept. It was beautiful and frankly, very scary. A lot of the animation has evil and devilish themes. Like this guy:
Also, the first one was made in the 1940's, so there are a lot of old Disney themes. I won't come out and just say it, but a great example is below of the centaurs that were matched with their colored counterpart. Ask me if you don't understand.
Of course, the infamous scene with Mickey trying out the sorcerer's hat is so good Disney used it in both films.
I liked 2000 more for a few obvious reasons: It was more to-date/modern, it showcased the technological advancements we've made to create quality animation and it wasn't as dark. They used different celebrities like Steve Martin, Bette Midler and Angela Lansbury to introduce the pieces instead of the same composer who I grew weary of in Fantasia. The stories were more interesting and I laughed - a lot. In fact, they were happy and uplifting. The themes weren't revolved around nymphs and centaurs but rather more definite characters like the Steadfast Tin Soldier. To me the centaurs and flying horses were more decoys than actual characters making it hard to sympathize with them.
I was going to write about my favorite piece out of the two films - the Gershwin piece illustrated by Al Herschfeld-inspired animation (above). However, after I've watched the film I forgot how great pieces like the flamingos with a yo-yo scene is as well as Donald marching animals onto the Ark to Pomp and Circumstance. My only beef with Fantasia 2000 is that it's too short - but it surely makes up for how LONG Fantasia was.
But, that's all just my opinion. Please, please go watch both and let me know your thoughts. Tell me which is your favorite piece. What bored you to tears? What scared you? What exercised your mind?