Halo 1 for the PC also has horrible system resource management for HD-style resolutions. But all things considered, it's still decent to play now and many people still use it.
Halo 2... That was just phail. I swear if I can only figure out how, I can find the Xbox emulator they built into the game to run it. Because there is no way that was a standalone port.
Halo 3 on the PC might have a horrible track record with Halos 1 and 2, but at the end of the day, if it came out, we'd pretty much all try it out at some point, and if it's good we'd probably keep using it. I just wish bungie would try developing Halo Reach for the PC while it's still in the Beta stage for the Xbox 360. The only reason I'd want Halo 3 or ODST on the PC right now would be to continue the story, and as we all know, the multiplayer is our main concern.