Others have pointed this out, but it needs to be simplified for mass consumption. Halo ODST was half a title, and the half that was missing was the really good half. Fans of the series really buy the games for the online multiplayer. The single player game is usually dwarfed. That was the problem for ODST it was basically the single player experience with a tacked on map pack that could just be purchased seperately. So as far as Halo titles go it was a fairly bad value unless you just had to play a last man standing mode. Beyond that while the single player mode was good fun it wasn't really a Halo experience. That said it is good to see Reach is working towards a more sandbox approach. That should really give the single player game more staying power.
Anyway ODST isn't very representative. Unless you say half a games sales are half of what a true titles sales would be. Halo wars on the other hand wasn't even the same genre. That all said I still have modest hopes for Reach. My personal opinion is that the series peaked with Halo PC. The maps were glorious, we were allowed to be solo artists, and my god those weapons were wonderful. Since then the maps have shrunk, every team mode forces teamwork, and we actually have less varieties of weapons. I want that flame thrower, and fuel rod gun back. They weren't cheap it was just a secondary objective to keep them out of the hands of the other team.
