depends on what type of rides you like... if your into thrill rides ride all the mountains at MK (splash, space + big thunder), rock n roller coaster, tower of terror, expedition everest, DINOSAUR, test track and mission space (sure there are others just not thinking right now...) also do the classic rides if you want (pirates of the caribbean, haunted mansion, it's a small world, carousel of progress if open,jungle cruise, etc.) and then there's just the shows you might be interested in (like philharmagic, it's tough to be a bug, lights motor action, sounds dangerous, beauty and the beast, etc.) then the 'other' rides like soarin', magic carpets, TTA, primeval whirl, kilomanjaro safari and so on...
of course there are others i haven't mentioned but i'm not thinking right (hayfever just makes me think less about stuff and more about blowing my nose, itching the roof of my mouth, etc.) so have fun when you go

(which looks like you come about when i leave...)