Off the top of my head: (excluding ILM people)
1. George Lucas (of course)
2. John Williams (composer on all six of the films).
3. Gary Kurtz (producer of "Star Wars" and "Empire Strikes Back")
4. Alan Ladd Jr. (The Fox Studios exec who greenlit the first SW film).
5. Harrison Ford. (improvised lines, rewrote dialogue on the set. Created a classic character).
6. Irvin Kershner (director of "Empire").
7. Marcia Lucas (for her editing work on the original trilogy, particularly the first two films).
8. Richard Chew/Paul Hirsch: co-editors on "A New Hope." Hirsh also worked on "Empire."
9. Lawrence Kasdan: screenwriter on "Empire" and "Jedi."
10. Alec Guiness (brought a respectability to the first film).
11. Frank Oz (performing as Yoda. Particularly in "Empire" and "Sith.")
12. Ewan McGregor (excellent as young Obi-Wan throughout the prequels).
13. Ian McDiarmid (perfectly cast as the Chancellor/Emperor in 5 of the films).
14. Willard Huyck/Gloria Katz (helped polish the dialogue on "A New Hope")
15. Chris Neill (Dialogue coach on Episode III)
16. Steven Speilberg (helped w storyboards on several action sequences in "Sith")
17. Ben Burtt (sound design man on the entire saga).
18. Leigh Brackett (wrote the original screenplay for "Empire")
19. Tom Stoppard (polished the dialogue on "Sith").
20. Roger Barton (helped edit Episode III).
21. John Dykstra (invented many of the visual effects used in the original trilogy).
22. Dennis Murren (visual effects supervisor on the original trilogy & Ep I).
23. Mark Hamill, Carrie Fisher, Anthony Daniels, Peter Mayhew (for their great chemistry on the 1st three films).
24. Hayden Christenson (for turning in a convincing Anakin/Darth Vader in Ep III)
25. The Star Wars fans: For not abandoning ship after "Jedi" and "The Phantom Menace." For waiting 16 years for Episode I to come out. For putting up with the constant changes and alterations to the original trilogy. Without them, they're wouldn't be a Star Wars phenomenon.
That sounded like an Oscar speech! Sorry...
I think Lucas should be on his knees thanking all the above mentioned people.....