First, I'd pay off all my debts, especially my student loans (about $37,000) and be sure to set aside enough for the rest of the classes I want to take. (about $82,000 if I make it into the graduate school I want - ouch!)
I have no idea what the taxes would be on that kind of money, so I'll just say a quarter of it goes to Uncle Sam.
I'd blow though...let's say $150,000 traveling the world, and my parents want to go to France so maybe $30,000 there so they can go in style. And $15,000 to my brother who would love to go to Switzerland (and Monte Carlo, especially with that much cash)
Then I'd send $100,000 to my favorite charity, Women for Women International, and save the rest so I wouldn't have to worry so much anymore. Good Lord, that's a lot of money!