Test Track and Mission Space are must sees, MS more than TT which is just an excuse for GM to show off their new cars at the end of the ride. MS is very clever but you really need a strong stomach.
Soarin is Ok, a good concept but its overhyped and missing something to make it a wow ride.
Living with the land is good, i really enjoyed the greenhouse tour bit
Spaceship Earth is dull zzzzzzzzzz, apart from the novelty of being in the golf ball, it didnt do much for me.
The World Showcase is pretty good but on a hot day there is no where near enough shade when walking round. Loads of good restaurants and places to get a drink so for that I rate it pretty highly

Lots to see and take in and you dont need to rush so the WS is nice and relaxing. If you've been to many of the countries shown it will make you a bit sad to see whole cultures reduced to a show, a restaurant, and a gift shop tho. If you're not a US resident and dont know what patriotism is, check out the American Adventure. Wow that was full on!
Inoventions is rubbish. Disney Quest isnt great but its more entertaining than this. The future of video games section is a joke. Its just games you can buy in the shops now.
Wonders of Life was shut when we went so I cannot comment and didnt get to do the Imagination Pavillion or Illuminations as the aforementioned lack of shade caused DW to contract a mild sunburn (her pale scottish skin was no match for the harsh Orlando sun) resulting in an early return to the hotel.
Not sure if its still on but the topiary and flowers from the flower festival were amazing.