I too a an organ donor. I think that if someone else can benefit from my organs when I'm gone thats great.
Autopsy, eh...if its necessary for some reason to bring those around me piece(life a murder, or accident happened and they wanted to know how I died) I am okay with that.
I am not, never have been, and never will be for embalming. That whole process freaks me out. That is completely unnatural, and I too don't want to be buried in some life preserving tomb. I'm Dead!! I want to go back into the earth for real, so cremation for me.