Well, when it comes to what I find myself thinking of the most, I usually like the one of the ending themes the most. What I'm speaking of is the theme at the end of ESB, during the final parts of the credits. In addition to there it has also been used in some of the trailers for TPM and AOTC, yet I do not know what it is called. Here's my half-comical attempt to convey it:
duuuuuh, da da da da, da da da da, da da da da, da da duh, da da duh, da duuuuuuuuh da da da da duuuuuh, da duuuuuh, da duuuuuh, da duuuuuuh, da duuuuuuuh, da duuuuuuuuuuuuuuuuuuuuuuh, dun dun dun dun dun dun dun dun dun dun dun, dun du du du dun.
Is a variation on other themes, obviously. But, I can't really say that it's my favorite, since there are so many to choose from.
Edit: I spent so much time on my little song that I missed your post Ken. I'll check out that site. It seems to be working for me, for now.
Okay, go here http://www.starwars.com/episode-i/video/epitrailer/epitrailer2.html and watch this trailer. What I'm talking about is the music that shows up near the end. There are also extended versions of that theme in other places as well.