Oh, man, tough question!
I think that the first thing I would do is pay off my credit card debt, and the various other debts that I have. Then I would purchase some of the things I really need at this point - a new bed, a new car, that sort of thing. I'd also spend a good $5,000 or so on stuff for myself and possibly a few things for my friends, and I would definitely take a vacation somewhere warm for a good month or so (hmm, a trip to Australia would be good!).
I also might be tempted to start a small science fiction bookstore again in the city of Ottawa with some of the remaining money, as I really enjoyed my experience doing that for most of the time that I ran Basilisk Dreams Books. Would definitely take a different approach to it than I did the last time, for sure.