Well I like RPGs, but mostly the kind that allow you to choose your fate kind of deal (see Mass Effect, Fable, and Fallout 3) I like them mainly because they offer more than just one long plot line, but many depending on how your mood is on a day to day basis. I know I don't always feel like being a good savior to humanity and would love to cause mischief or flat out carnage some days.
The other type of genres I like are Strategy and FPS. Strategy makes a person think and be creative, yeah, school learning type stuff. As with FPS, it's non-stop action, so there's no time to really get bored.