Me personally, I'd buy any new computer hardware within price range. My main bottle-neck at the moment is having a 1TB drive with everything on it.. So, I'd probably go with a top of the line 60GB SSD (Less than $200 now, prices have gone down) for the OS, and keep my crap on the old drive. What ever cash is left over, I'd do as Dirk said and click the big golden PayPal link located on the bottom of this page. So, I'd say buy something you really want and would make something a little better for you and then just donate whats left over. Unless you are feeling generous, then just donate all of it! [^]
You throw that money in the bank and save for a rainy day when you wish you would of had it... Just don't rush out and buy something. I would save it in a bank where interest can occur on it.