Re: Halo 2 pc questions
360 controllers is a matter of plug and play, wired controllers go right into a USB port, and wireless controllers need a wireless receiver, but are also pretty much plug and play, and yes you can fully use them with games such as Halo 2 and Shadowrun. Also many other games fully support them, for example if you play a game like Overlord or Lost Planet then it uses the exact same controls as it does on the 360 if you select that controller, it even shows you the 360 controller in the menu's etc.
And yeah, try the game.
Btw i'm not sure how much of this works with Halo 1, when that game came out the 360 didn't exist yet, and the Xbox controller can't be normally used on the PC (it uses special plugs instead of the USB plugs from the 360)