Provided I have enough money saved up, I want to be cryogenically frozen so I can be revived when whatever went wrong can be reversed, even if it's 100, 500, or 1000 years from now.
If that's not an option then I want to be cremated and ashes thrown to the wind or used as fertilizer. An idealistic use would be shot into space, but that'll just make me end up being the flying debris which probably hits a spaceship some day, crippling their warp engine. XD I suppose just being shot into a sun wouldn't be so bad, though.
Once I'm dead, and there's no way to preserve for reviving within my means, I honestly don't care too much what happens to me. It's someone elses problem.
Actually, now that I think about it, barring cryogenic freezing, donate my body to science.