Best Game Controller for the PC?

360 controller has worked like a charm for everything with any kind of controller support for me, haven't had an issue yet. I use wireless, for what it's worth.

I use Razer Onza, I don't have big problems with it.

If anything, the Xbox 360 controller is the only one officially supported gamepad, the others are just supported by the virtue of using the same interface or emulating the 360 one. Ultimately it depends on your preferences, e.g. do you like it better if the analog sticks are in one line or not? What about good grip? Comfortable d-pad? If you don't care particularly about any of these just get the X360 controller, the wired one as it is the most hassle-free of the lot. If you are a Playstation user you might wanna look into plugging your controller in PC and emulating the X360, but they the button prompts in games won't match. You can also get a cheap or different copies of famous brand controllers, but the usual caveats apply for such purchases.

Speedlink Xeox Pro (wireless)

Bought two for my gf and myself and they work like a charm :)
(x360ce and other programs help you remap whatever gamepad you'll be using :) )

Mouse and keyboard. But the X360 pad should be fine if you really want to use a gamepad for whatever reason. Bought a couple myself recently to play platformers together with my wife.

Xbox 360 wired controller

Most games since 2007 support it.

xbox 260 controller is the best for pc

I would consider the X360 controller... Or the Logitech F710, it's an excellent option as well.

360 controller is okay, I have one, too. I just wish the control pad (not the analog sticks) would have separated keys for each direction.

Xbox 360 Controller For Windows if you want it just work right away.

DualShock 4 (PS4 controller) now that there are fan made drivers out for it. DS4 to XInput Wrapper
This 1.3 Driver specifically allows use of the touchpad. Which is nice when you want to do a small bit of mouse control with letting go of the controller.

The 360 controller will work natively for any x-input games. Older games using directinput might have issues where you need to use something like xpadder to configure the buttons

Mainly a mouse and keyboard user myself, but I have recently got an Xbox 360 wired controller. Plugged it into my PC and was playing games with it within minutes with no 3rd party programs or even MS programs and I haven't used a game pad since SNES days.

Pretty much any version of it will do. I got one with the model number 52A-00004.

Wireless ones are ok, but you have to consider a few things. You also need the wireless connector so that the controller can connect to the PC. You also need batteries so if you are playing a game and you haven't charged in a while it could die on you in the middle of the game.

As for games, well many support controllers in general. I'm mainly using it for pinball games (like Pinball FX) and SHUMPs (like Sine Mora and Satazius). It works for stuff like Borderlands 2 and some driving games but I haven't tried it with them yet but going by some videos I have seen on youtube people don't have any issues with it.

I'm on Windows 7 64bit but should work fine for any other version of windows.

Logitech F710. Works perfectly and you don't need any sort of programs either,
It's that controller Steam has in the Big Picture mode, btw. :P
I have this one, bought it 2 or 3 weeks ago. Works like a charm and I couldn't be happier with it.

Plus... we all know Logitech stuff LASTS FOREVER. (From my experience that is. :3)

I used Razer Onza for a few months and it was amazing. best controller I have ever used (I don't play consoles since ps2). it's like an upgraded Xbox 360 controller. unfortunately it broke down after a few months and I have to get a warranty, and because by then the product had been discontinued, I had to pay a lil bit more to get their newest and only controller, Razer Sabertooth. that sh*t is crazy overpriced, about $ 80. it's good if you want the extra 6 buttons and an LED screen to save your settings. as I said, it's over featured and overpriced.

I use the Xbox PC compatible controller. It works great with all the games I've tried.

EDIT: I think mine automatically downloaded a program.

keyboard+mouse

The Xbox360 controller seems to be the most popular due to the simplicity and support it has.

I personally use a PS3 controller as I prefer the stick placement. Hopefully we'll get some official drivers someday as both the PS3 and PS4 driver are fan made.

EDIT: I just saw your edit, Windows should automatically find drivers for the Xbox360 controller once it's plugged in. If a newer game has controller support, then it'll recognize the controller. Any older games that don't have controller support will require a secondary program such as JoyToKey which will detect your controller presses and send keyboard strokes in place of them allowing you to use the controller.

For the xbox 360 wireles adapter (+controller) i just googled " xbox 360 controller wireless microsoft drivers" one of the first results were a microsoft link with the drivers. downloaded them and it worked flawesly. Any new game (>2008) has excelent compatibility for this controller. Older games might support it or not. If they don't you can use some programs to emulate the keyboard. this was my objective experience.
In my opinion, i highly recomend the xbox 360 controller (especially the wireless version) over most PS3 controllers. Mainly because the thumbsticks and triggers make the controller better to use in most games then the PS3 counterpart. Still it boils down to preference.

For pc? keyboard and mouse. nothin else

Well, not sure if it's the best controller around for PC... but I use a Logitech Gamepad F310.
It's got a little switch on the back of it which changes it from X-Input to DirectInput.
As far as I'm aware X-Input makes it function as an Xbox 360 Controller would.
I also think it's just Plug And Play, meaning you don't really NEED to install anything extra, though there are things you can use to configure it for certain things and all that.

For shooters/RTS you really can't beat Mouse+Keyboard in my opinion.

If you must use a controller for such games, it's pretty widely accepted that the 360 controller is the best choice.

For other games, the 360 controller isn't a terrible choice (though the D-Pad is kind of atrocious) but the PS3 controller is easily the most versatile controller.

For fighting games, The 360 controller probably edges out the PS3 controller, though a proper arcade stick is the best way to go for sure

Many games will support controllers natively, but for those that don't Joy2Key will allow you to bind keyboard/mouse inputs to any controller, giving you total coverage.

I use an xbox 360 wireless controller + usb dongle and I love it. The wireless controller sold with the dongle marketed as 'Wireless Controller for Windows' and the wired USB one that also says 'Microsoft Xbox Controller for Windows' are exactly the same in every way as the xbox controllers for xbox. You can use both with your xbox (if you have one) and your PC and vice versa. If you already have (or can source for cheap) a wireless xbox 360 controller, you can buy the dongles separately on Ebay for about $15 USD although I've only ever seen them bundled with controllers in stores.

I'm pretty sure my controller came with the drivers on a disk but if you don't end up buying the wired controller or the wireless pack you can just download it from the MS website, a quick google brings up the right one. You don't need any annoying client software or anything to use it. The wireless controller + dongle works flawlessly and I've never once had issues with the connection dropping out and the controller works quite far away from the dongle, I've never had to move closer to make it work or anything like that. More games now have controller support but for any game that doesn't, you can download Xpadder (or similar) which lets you map mouse and keyboard keys to controller buttons.

The Logitech F710 is pretty nice, but you can get a 360 or PS3 controller to work with a PC just fine. Check Google. I also hear the PS4 controllers work on PC already, and I assume the XBOne works just fine, or will with 3rd party drivers.