Elsewhere in that Word doc hosted on Xbox.com that listed all the upcoming accessories, was the (as yet still unannounced) Xbox 360 Wireless Gaming Receiver for Windows. What is the Xbox 360 Wireless Gaming Receiver for Windows? From the doc:
"Gamers can get the most out of current and future Xbox 360 wireless accessories with the new Wireless Gaming Receiver for Windows. By plugging the compact receiver into a USB 2.0 port on the PC, the Xbox 360 Wireless Controller, Xbox 360 Wireless Headset and Xbox 360 Wireless Racing Wheel can be used on a second platform (ERP TBA)."
That means you won't need to get the (now increasingly marginalized) wired 360 controller if you want to use it with your PC. Question is, how long before the Xbox 360 Wireless Gaming Receiver for Windows gets support for other operating systems?
360's Mem Unit getting a bump to 256MB?
Read - Xbox.com's Xbox 360 Accessories (.doc)