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Xbox 360 controllers work pretty well for most games.

https://steamcommunity.com/groups/steamuniverse/discussions/0/864980009937564570/

You can use them no problem whatsoever with tools like MotionInJoy, SCPToolKit or JoyToKey, if other solutions shouldn't work.

I use a LogiTech F310, works for everything I've ever tried. You can get one cheap on Amazon ($15-$20).
At one point I had a PS2 to USB adaptor and used a PS2 controller. xD
Programs like the ones mentioned by Skibby never worked for me.

I play rocket league with my Dualshock 3 and SCP because motionjoy is really bad :)

Every game is going to be different. I'm using a PS2 controller with a USB adapter. Most games don't recognize it, so I use the program Xpadder to bind the controller buttons to the keyboard keys that the game uses. There are other programs that others mentioned above that do the same thing.

The game I am playing now, Super Panda Adventures, recognized the controller and allowed me to rebind the controls in the game, but it is rare.

Better Ds3 (works offline)
There was an offline version of MotionInJoy but i can't find it anymore

I can recommend the SCP drivers, I've had no problems with it. It only requires a one-time configuration and you're set. Tzaar already linked you with that Steam community guide, but here's a good video tutorial that I followed when I did the setup. How To Easily Connect PS3 Controller to PC (No Motioninjoy Required)