I've got U3, and believe me, you really don't want it. Unless you use public computers frequently and would like to use your own programs and such, it just gets annoying to have to wait for the U3 thing to load every time you plug the thing in.
Anyway, if you're ordering offline, check out this:
Other than that, I have a PNY one that's great, and I know Sandisk and Memorex are both excellent quality.
I own two of these:
EDIT: 1k POSTS!!!! W00T!!!!!!!!!!!!!