Xbox 360 controller if you have Windows 7 or Vista.

Just hook it up and play.

I have two Logitech rumblepad 2's and two wireless rumblepad 2's so I have some spare..
I prefer them because of the square axis limits, buildquality and the easy to use profiler software.
The only thing is that of the wired rumblepads the shoulder buttons tend to not register sometimes because of too low tolerances, I fixed that with a bit of grease on the side of the buttons.
The pads are DirectInput only but you can use x360ce for games that need Xinput.

Had Logitech f510, Xbox 360 wired and ds4 controllers until now, felt like ds4 was the best fit for me. InputMapper made it support xinput games perfectly so no problems with that either. However I did have troubles with Bluetooth connection to laptop for a while till I put in proper drivers. (Worked fine at first but then started acting strange like not connecting despite being in vicinity)
Have relatively smallish hands so if yours are small go for ds4 otherwise you might be better off with Logitech ones (value for money) or Xbox controllers (comfortable grip IMO over Logitech and sticks/buttons felt better, kinda rigid in f510)

I use my ps3 controller and scptoolkit

Best not to take any chances.
Get one that covers all of your needs.

I often have issues with my controller not responding after restarting my computer. This is solved by just unplugging it and plugging it back in again (and with the extension cord & dongle, that's done really fast). It's mainly just an issue if I forget to do it before starting a game, as that means I'll have to restart the game for it to detect the controller (and some games have annoyingly long loading times).
Using Win 10, by the way.

I got lucky and found a wired Xbox360 controller at a little store called "Here Today" for $15. I'd recommend it for PC. I've set up a number of controller profiles for it using JoyToKey.

I used to use a wireless Afterglow PS3 controller (which I prefer, oddly enough, even though it's not quite compatible with certain Steam games. Mostly Valve releases.) The thumbsticks were more responsive and not as stiff. I lost the USB connector for it in the process of my friend moving out.

It might be hit and miss with Xbox controllers though. I had bought a Wireless Xbox360 controller for Windows, which came with the wireless dongle thing which was pretty neat, but the sticks drifted in a certain direction. Plus, you'll either have to keep spending money on batteries and hope the battery clip doesn't break OR purchase rechargeable batteries and a charging kit/stand and still hope the battery clip doesn't break :D

My advice. Get wired.

On mine the shoulder buttons kept breaking. I went through SEVERAL controllers because the mounting brackets for the bumper buttons is absolute crap. I use a wired 360 controller now and have very few complaints.

EDIT: Xinput plus makes using the pad with DirectInput fine. It can easily switch between the two with profiles saved in a by-game basis.