I'd probably have a list of things, and I'd want my stone updated every week, like a facebook status.
So, name at the top, followed by one of the following:
"This hell thing looked so much easier to deal with in Dante's Inferno..."
"is rushing some form of hellspawn. 'LEEERRROOOOYYYY!'"
"is wondering about the length of the respawn timer"
"If the zombie apocalypse happens, I apologise to any loved ones my reincarnated corpse assaults. If you're not a loved one, I look forward to devouring your brains. Omnomnom"
And, of course, since it's Terry Pratchett status week at the moment
"Is this my cow? It goes . That is a demon. That is not my cow"
I also want my avatar on my gravestone.