Halo PC is free to play online and has low requirements. Halo 2 Vista has stupidly high requirements and still doesn't require you to pay to play online. Recently MS made it so hosting is free on H2V, IIRC.I said Halo PC, not Halo 2 Vista, :P my PC doesn't have enough RAM for it. The requirements are ridiculously high and it forces you to pay for online use anyway, I'd rather just have the XBOX version of Halo 2. xD
Halo PC = Halo: Combat Evolved.