All videogames under the format "Games for Windows (R)" can use an Xbox 360 controller, but to use an XBOX 360 controller for this type of game, you need a special adapter. Purchase a new XBOX 360 Wired Controller as all new controllers include a USB port adapter attached to the cable-jack that would normally fit into the slot on an XBOX 360 console. Look up "Games for Windows (R)" on wikipedia.org for more information.
Microsoft has Dual Released a lot of there titles as of late on the both XBOX-360 and the PC. (oblivion, The last Remnant, Dead Space. To name a few) Also you might want to check into the free program called switchblade in which you can control your whole computer (mouse and all) with your Xbox-360 controler.
Many Games, but only some are playable for the xbox 360
no
No, you cannot play GameCube games on the Xbox. Only Xbox games are playable on the Xbox.
You'll buy PC games. The XBox controller can be used with some PC games as a standard video game controller.
Currently, 74 games support the Xbox 360 controller as a dedicated PC controller.
Yes, they are.
yes the are
I don't think the games are reverse playable
http://www.xbox.com/en-US/games/backwardcompatibilitygameslist.htm
No, you cannot. The "Original" Xbox cannot play Xbox 360 games. However, a list of "original" Xbox games are playable on the 360.
no, only on a Xbox360
Most xbox games are, The best way to findout is to google search xbox 360 backwards compatible chart