I play strategy games, first person shooters and 3rd person shooters with my mouse and keyboard. In essence all games. The mouse provides finer control which means better accuracy. However, if you have been playing mostly with a controller then I suppose switching to keyboard / mouse will be a learning curve. Much like how it was a learning curve for me to play Halo and Halo 2 on the Xbox with a controller.
Probably the only game that I will likely not use mouse and keyboard will be Star Citizen (not released yet) which is a space combat sim that is being developed by Chris Roberts (who developed the classic Wing Commander and Privateer series). For these types of games I prefer to use a joystick, keyboard, and throttle.