OOOhhh....
I'd buy my sister a house and two new cars for her and her husband. I'd set aside college tuition for her children.
I'd buy my parents a house and two new cars and have them retire. They would never need to work again unless they wanted to. Money wise they would be covered for the rest of their lives.
I'd buy a new house for my wife and I, new cars (something reasonable, not a ferrari or anything silly like that), a loaded Mac and a bunch of camera and audio gear, a Cintiq tablet, tuition to a school that teaches concept art and design techniques. (not a full college I've already done enough of that, I mean something like a www.gnomonschool.com or the likes). I also buy a marimba as I really miss playing.
I'd start a shell company and hire my 10 closest friends to "work" for me for the next 2 years at $100k a year salary each.
I'd start a real company and hire some of my art, music and programing friends so we can develop some great games for computers, consoles and the iPad.
Vacations to Hawaii, Japan, Vegas.
The rest gets saved away for retirement and the ability to just enjoy life without worries.
I'd start taking much better care of my body and become a much more healthier person. Which I want to do anyways.
My one wtf silly purchase: a complete set of every TSR/Wizards D&D book/module/etc ever released and put them in a custom crafted cabinet with glass doors in my game room.