1st World Problem right here!

Go on big picture and then to your library and there is a check box in the right side that say "compatible with controller"

You could try using http://www.lorenzostanco.com/lab/steam/ and click on the "controller" filter (after loading up your library). I personally love that site, makes it easy to see my games by tags.

Edit: Or do what the person above me says. :P

Battle Block is great on controller

I'll give you my personal "rule":

• anything that has a pointer: mouse
• FPS: mouse and keyboard
• simple retro games: keyboard
• everything else: controller

I know many others use mouse and keyboard much more... That's the beauty of PC gaming, right? Diversity and freedom!