Aw, jeez, I don't know. I don't want to be buried because of the off-chance that I might actually still be alive, which would be friggin' TERRIFYING. That, and I don't want to decompose into nothing. Just icktacular... And yes, I know I'll be dead, it doesn't really matter, etc. But I just don't like the idea of my body, whether lifeless or not, rotting away in a box. I dunno...
And with cremation, being on fire scares the bejeezus out of me. And so much so that I actually turn into ashes? Blegh, awful... Again, I know that it won't really be me, but rather my soul-less vessel. But still... Ugh, I'm such a wimp. Although that using your ashes to turn into a tree idea sounds very nice indeed.
In any case, if my organs and junk are still good to go, then I'd want to donate them.