Definately go to all four theme parks if possible.
Magic Kingdom has the most to do, in my opinion, so definately stop there. Be sure to ride all of the MK's Mountains (Splash Mountain, Space Mountain, and Big Thunder Mountain Railroad- especially at night!) if you enjoy coasters- and getting wet!
EPCOT is more of a place to dine in my opinion, but there are also several things to do and ride. If you have children, try the new Kim Possible Mission thing in the showcase- I haven't tried it yet, but I've been told it's a lot of fun for little ones. There are also attractions such as Test Track, Spaceship Earth (one of my personal favorites), and Soarin'.
Disney's Hollywood Studios (formerly known as MGM) is a place of glitz and glamour- my second favorite park.

If you like scary rides, try Tower of Terror. Once again, if you enjoy coasters, you'll also want to add Rock 'N Rollercoaster to your list- especially if you like Aerosmith! There are also a lot of shows to watch here- my favorite is The Voyage of the Little Mermaid. If you look closely by The Voyage of the Little Mermaid or One Man's Dream (I can't remember which one is the entrance) you'll find an entrance to enter a little show that tells you about cartoons- starring Mushu from Mulan- and if you go into the seperate room after the show, you'll be taught how to draw a Disney character. It seems boring at first, but it's a lot of fun, and only about ten to fifteen minutes of your time.
Animal Kingdom isn't very much my favorite, but you might want to stop here to see what it looks like. It's actually very gorgeous, what with all the trees and flowers and life in there. Make sure to ride Dinosaur and Expedition Everest- and be on the look out for the yeti!
Have fun on your trip!
~Popperz