Let the hive mind of Engadget get that for you.
"I am trying to configure out a really dumbed down and intuitive PC for my grandmother. She recently had a stroke and while she is under my care I would like to repurpose a laptop for her to surf and email her children. Anyone have any experience with what input devices and UI's are really understandable for the over 80 crowd?"
Have a look at the Second Life Blog posts. They contain two examples of resident created stuff.
They've also got their benchmarks that run 22000% faster on the wiki page. http://wiki.secondlife.com/wiki/Mono