Well, at this place you're probably going to get this advice quite often: Invest in several startups. Just what YC themselves do.
I'm the CFO of a tech startup myself. We are building "The Instagram for online trade". I'd love to talk to you.
If it were my money I would invest a portion of it in startups (but you must obviously know that the risk of losing these money is present), and I would invest most of it in stocks and keep the rest in the bank. I have some personal recommendations, but if you don't have any idea on the stock market I would consider contacting an investment bank. I think that would be reasonable with your amount of money.