As someone with a serious heart condition, I've probably put in more than my fair share of time thinking about this topic/considering the options. And just when I think I'm certain I know what "my wishes" are, they change!
I do love this idea as a lasting memorial for a loved one though:
http://www.lifegem.com/index.aspx?BType=YTxt&BAg=HCrem
As for my 'death preference', quite honestly, I wished to be drugged out of my gourd, feeling no pain, nor fear, if possible.