I'm sorry but your comparing a full blown sequel to what bungie has called an expansion pack. I am going to keep my eyes on Halo: Reach which may be a more comparable game since it seems to be a more blockbuster game, but honestly I still know very little of that game so I can't say much on what I think about it. Modern Warfare 2 is looking fairly promising in the single player mode which is good since thats all I really liked from it(Multiplayer was extremely repetitive for me) though I have yet to actually play either of them. My best guess is that Modern Warfare 2 will be better since it is not going to be a sub-story of something bigger, and is expected to have a longer campaign. ODST is supposed to have a Multiplayer Beta for Halo: Reach and so I might get it for that reason(though the last game that had a halo multiplayer beta on it was pretty good so who knows)
