So I ripped myself away from Halo 2 long enough to confirm that's it's great. The Xbox Live component is too fun. Unlike many other games, the connection is seamless. No lag whatsoever. And having a clan is too cool. You round up your posse and take on other clans. Then check how you performed on bungie.net.
Everyone, get an Xbox, then Halo 2, then Xbox Live. Do it now.