Not the cheapest, but I would go with official Microsoft wired Xbox 360 controllers, they have the highest compatibility. Xbox one controllers have the advantage of working on an Xbox one, but the compatibility is actually less than the 360 controller on pc.
You also don't want to go with an off brand like mad catz. Believe it or not, different brands and not recognized the same way on pc. Even though they are both Xbox 360 compatible controllers, an official Microsoft controller is much more compatible with pc games than another brand like a gamestop or mad catz... plus the quality is better.
Now as far as hacking you are gonna have to be at least decent at soldering. Everything is pretty straight forward except for the d-pad. The contacts are tiny, but there are alternative solder points for the d-pad on the back of the controller and I recommend using those...
See this diagram.
http://slagcoin.com/joystick/pcb_diagrams/360_diagram1.jpgKeep in mind that many PC games only allow you to use the left analog stick for controlling your character, so you may want to test the games you want to play first to see if they allow you to use the d-pad for control... You can wire a joystick to the analog stick but its a bit complicated and not ideal...