Jules,
Concerning your list:
1. Star Wars (4, 5 & 6)
2. Blade Runner
3. Dune
4. Alien(s)
5. 2001 a Space Odyssey
6. Close Encounters of the Third Kind
7. Contact
8. Signs
9 Terminator
10. Matrix
I don't think I've ever seen "Contact" either, and I will just have to TOTALLY disagree with you about "Signs!" Signs is one of the few M Knight Shyamalan movies I DON'T like! Right up there with "The Last Air Bender." The Village, Unbreakable, Lady in the Water, Sixth Sense, etc. loved 'em. Signs - oh man that was painful!
Not to change the topic from your custom vehicle, but since you listed Alien(s) have you seen Prometheaus? I thought it was pretty good! I've never thought of a top ten list of favorite sci-fi movies. Off the top of my head I'd have to list (after no. 1 no particular order):
1. Star Wars ANH (It's my favorite, but I think TESB is the best of the entire franchise)
2. Blade Runner
3. Matrix (I prefer "Reloaded" over the other two)
4. Transformers the Movie (1986) I know it's a cartoon, but made an impact as a kid!
5. Priest
6. Total Recall (the Arnold version)
7. Star Trek (JJ Abram's version, totally rewrote the franchise - excellent!)
8. Transformers (Michael Bay, the first one. The second sucked because of the filthy language, and the third sort of made up for it)
9. Robocop
10. Battlestar Galactic (Sci-Fi, ok it's not a movie but series was the best t.v. show I've EVER seen! I loved that series better than Star War!! Colonel Tigh was mine and my wife's favorite).
Jason