If you're only gaming you really don't have to worry about calibration. There are a couple games out (Crysis 2 for example) that will grab your color profile after you exit the game and not let go until you reset it though.
I've used several calibration devices over the years for photography that requires accurate color. Spyder, Eye-One, Colormunki, etc. Of those I really like the Colormunki. It's extremely fast, super accurate, hands off the monitor buttons, and can also profile other devices like printers, and projectors so that you have a completely matched system.