Making a two year old Xbox game the first Vista only title was probably one of the most bizarre decisions made by Microsoft lately. First of all, Vista is supposed to be a next-gen operating system, so using a game that barely has any DX9 functionality is kind of dumb. Secondly, from the millions of gamers out there the majority of those who wanted to play Halo 2 already did it on the Xbox. That leaves a relatively low number of PC only gamers as potential buyers, but even then only a fraction of them are running Vista. So what was Microsoft thinking I ask you?