Channel 9 recently talked with Jeff Henshaw (Xbox) & David Alles (Media Center) and got down to the nitty-gritty of the Xbox 360's relationship with Windows Media Center. You can download the entire interview, here.
The components the guys recommend:
720p native HDTV
802.11a (for wireless network users)
Dolby Digital Surround Sound (with optical input)
Check out: Online Spotlight