Hey there.
The least hassle and working straight OOB solution would be to go for a (wireless) XBOX360 pad.
Thing is, I hate them. I abhor them. They fill me with misanthropy, rage and utter blood lust. They are no good for me.
The XBOX360 controller does not make sense for my hands or my brain. In my books, it's just a desecrated PlayStation controller, ripped apart and screwed together upside down and otherwise mutilated, so Sony couldn't sue Microsoft for infringing upon their patents. So, I am not the most neutral person on the subject.
I am very fond of the Logitech Cordless Rumblepad II, since they are rather similar to the more symmetrical layout of the PS3 controllers. In fact, I/we use 1-4 of them when playing just about anything. There is absolutely no problem with emulators or most PC games that I know of. Each controller comes with its own USB receiver, setting it up is a blast.
BUT...
Since Microsoft expects you to use an XBOX 360 controller, though, you would have to get fixes/patches for every game so the buttons match the layout of the Logitech controller. Also, the more current games will display XBOX controller buttons on-screen, which takes some initial getting used to, as you'll have to brain-map everything before it's stored in the auto-correct subsystem of your brain.
If that does sound awfully complicated to you, it's got to be the 360 controller. Since you already own an XBOX, and probably have less issues with the controllers than I do.
You could just use the wired controllers you already own with your PC. Not sure if that would be an option. I don't like cables and wires much myself.
To be able to connect a wireless controller, it is suggested you use an 'Xbox 360 wireless gaming receiver'. That's probably easiest.
I have tried to connect PS3 controllers, and I succeeded, but it felt clunky and very... unsatisfying to me. I haven't tried that for years now, since I'm happy with my Logitech setup.
Helpful Microsoft/XBOX entry on the topic: http://support.xbox.com/en-GB/games/xbox-controller-for-windows-setup
Contrary to what some people say, Microsoft strongly suggests to install the appropriate drivers BEFORE connecting the XBOX 360 controller(s) to your computer. Now knowing about your PC/computer/problem solving smarts, I'd want to agree and just go with that.