Cremation sounds romantic but you're ultimately just sat in an urn or scattered, so either you clog up personal space or catch some poor sod in the eye. Burial just takes up more space in the finite lands of Earth, although giving back to the planet is fair game in natures cycle. Donation sounds okay, you save people and you're in nice clean jars rather than a ditch or a pile of ash.
Turned into a diamond just sounds sort of vain, and kind of camp as well. Look at me sparkle guys!
None of this matters to me anyway, I just need my Odinsleep and it's all dandy again.