I tend to buy games that are either a)really good single-player, or b)really good multi-player
Games that I've found that are worth playing at least once, if not more:
Halo
Star Wars: KOTOR
MechAssault
Morrowind: GOTY (but I'm sure most people would prefer the PC version)
Jet Set Radio Future
Medal of Honor: Frontline
Blood Omen 2
Conker: Live and Uncut (not out yet, but pretty much the same as the N64 version, which was really good)
Gauntlet Dark Legacy
Legacy of Kain: Defiance (though, I'd wait to see if a PC version is released)
other people may mention:
Soul Calibur 2
Alien vs. Predator
BG: Dark Alliance
D&D Heroes
Max Payne
Need for Speed Underground
Serious Sam
Tom Clancy's Splinter Cell
Fable (winter 2003)
XIII
Prince of Persia
and whatever sports games suit you the most.
BTW, you should check
xbox.com for the complete list. There you can find screenshots, trailers, links to the official site, game features, the suggested price, and when it was/or will be released.
[ 11-30-2003, 09:31 AM: Message edited by: Nanobyte ]