The answers REALLY varied on this one... a welcome event from my perspective.

46. Ludicrous Speed
by chubbs peterson

45.One that blows up a random TIE fighter for no particular reason [while the officers have bets on which one it'll be]
by JediNemesis

44. The one that came off Needa's uniform when Vader strangled him.
by JediNemesis

43. The Omega-13
by Simon H. Johansen

42. "Coke", "Diet Coke", "Fanta", "Sprite", and "Dr. Pepper".
by Keith

41. If you have just screwed up badly, press here and Darth Vader will be with you shortly.
by Keith

40. The "Dump The Garbage so the Rebels can fly away" button
by Jaux

39. "Press to intensify forward fire", though it seldom works...you just get an error message saying "too late!" most the time
by Eren

38. The button to kill Bantha's from 20 parsecs away....with MIND BULLETS.....thats Vader's telekenesis Kyle... (obscure but extra kudos to the ed if he can figure out where its from)
by Eren

37. Buttons? Who needs buttons? They've got JOYSTICKS!
by Gamingboy

36. Main Bridge Shields (unfortunaltly it was written in Chineese on "The Executor")
by Darth Lars

35. Sorry no button on the bride for Warp Speed Plaid, there however is one for Flannel!
by Emperoress Palpatine

34. Hello, OnStar? My Admiral is having a Sith-Induced Respiratory Constriction! Where's the nearest Bacta tank? Or can you just send an MD droid?
by Long-Gon Jinn

33. "Fluff and Fold". (They always put the laundry machine controls in the weirdest spots...)
by Jedi Sanity Master

32. Surround Sound. Play that evil music white-suited boy!
by Leiaway

31. pizza hut on speed dial - the imperials take full advantage of the "delivered in less than 30 minutes or it's free"
by canada ham

30. The elusive 'Any' key.
by Padawan Drew

29. Automatic "Imperial March" player button
by Sithdrummer

28. The Eject Trash Button (I mean who really controls this? Is it just some little cadet whose only job is to eject the trash?)
by Dark One

27. "Update TFN Video Games caption action"
by The Sith Gamer(He takes shot at me all the time, i can give one back. :) -Ed)

26. How should we know? There's a hundred thousand blinking buttons on the bridge, and they're all unmarked.
by Rin, Destroyer of Keyboards

25. Imperial March Novelty Horn
by Peregrin Toker

24. "STOP," "GO," and "FIRE." Star Destroyers don't really do much more than that.
by Macaroni Penguin

23. Press and Hold to reboot Windows 98
by Thrawn's Master Apprentice007X

22. A, B, Select, Start, and of course a direction pad for steering...
by BCDS DDS SW Fan

21. Thermal exhaust port close (must have been broken that day)
by ChrisZ

20. WORKING tractor beam
by JediGavin

19. Button that makes the Wooooooooo sound.
by zzzz

18. Well, there's two or three buttons on Darth Vader's chestplate, but I wouldn't reccommend pushing them.
by Kyra

17. British Accent Simulator
by Darth Luminara

16. How 'bout top 46 buttons NOT to push on a Star Destroyer. Like the Exit Hyperspace on the Wrong Side of Hoth button.
by Long-Gon Jinn

15. The oft-used 'Deploy the Fleet" button.
by Cirrocco

14. Press here to change the size of the Star Destroyer in relation to the camera angle currently used
by Darth Becker

13. One button transforms the Star Destroyer into an 18-wheeler by the name of "Maximus Prime."
by Tycho Celchuuu

12. "Fire Laser" with three settings: "Miss", "Way Off", and ""Is there anything even in the general direction of where the laser went?"
by Darth Koopa

11. Are you compatible with Natalie Portman? press here
by Morgoth

10. D4.... Battleship sunk!
by Peter Tutham

9. Palpatine's. Oh...NOT to push.
by AJP Darth_Lucky

8. Admiral Piett (?): "Hmm, this button says 'Gravity Control'...." *looks up* "Hey, an A-Wing!"
by Kupokpok

7. Admiral: "Release the ysalamir" button? SO THIS IS HOW HE SURVIVED FOR TWO EPISODES!
by rabid jawa

6. Electromagnetic Pulse...it's the only weapon we have against the machines......shhhhhhh...... (Matrix Plug)
by Elextron

5. "Please Don't Push This" submission #4,534,101
by Elextron

4. For the ranking officer: a button that activates a big neon "HE DID IT" arrow sign that points at one of your subordinate officers. Handy for when you slip up and let the Rebel scum know you're coming
by NAHTMMM

3. Disguise Kit Button - Turns Star Destroyer into a Shoe or a Potato, depends on how you look at it.
by Emperoress Palpatine

2. Smite.
by Darthlucky

1. For those looking to escape, red pill dispenser.
by Jedi Master Lou