This blogger has put together a list of science fiction themes that have been done waaaaay to death.
If you read or watch a lot of science fiction, you may begin to notice certain themes that constantly crop up. Some of these, like the ridiculously sexy female scientist/alien/robot/whatever, detract from the realism — but no one is complaining about it. Not me, anyway. Hooray for Jeri Ryan!
But some of these overused cliches really need to go.
I can think of a few he missed, like “ships that are capable of FTL fight battles with laser-type weapons,” but I think he definitely hit the major offenders. (Beware: The page was recently Farked, so many of the comments are of the Asshat variety.)