I went with Tomorrowland, though I'm still thinking about a year or so behind. I think the perfect Tomorrowland was right after Stitch opened (yeah, yeah, no one else agrees. I like it better) and while Timekeeper still existed. My rankings
1. Tomorrowland - Timekeeper, Buzz, COP, Space Mountain, the TTA, Stitch, and Sonny Eclipse. If only Disneyland's Tomorrowland rehab had gone so well. Then there's that background music (both recent versions). All in all a practically perfect land. I hope they know what they're doing putting Monsters, Inc. here.
2. Frontierland - Splash Mountain, Thunder Mountain, and Country Bears.
3. Fantasyland - Peter Pan, Small World, Snow White, Pooh, and I guess Philharmagic.
4. Adventureland - This might have been #1, if not for Under New Management and the abbreviated version of Pirates. But the Jungle Cruise is still incredible.
5. Liberty Square - Haunted Mansion and the Hall of Presidents (before 2000 and after 2008!)
6. Main Street - Love that choo-choo and the great background music.
7. Toontown - Goofy's Barnstormer, I suppose. There's so little here compared to Disneyland's Toontown...