Personally, I think it's far too late to bother with Halo for the PC. I mean, if it had been last year, sure, I would have strongly considered picking it up. Year before that, hell ya, I would have gotten it. But since I've played the living hell out of it on the Xbox in many a fragfest, and beaten the single player over and over by now, no way am I gonna go run out and buy it for the PC years after it came out for the Xbox just so I can play online. whoopitydoo!
Now, if they can get thier butts in gear, and get a PC release of Halo2 out sometime in the same quarter as the Xbox release, I'll be all over that like white on rice. (I'm not gonna be stupid, and hope they release a PC version of it at the same time as the Xbox version, but I would like to see it in less than 6 months after the Xbox release, not 2 1/2 years later.)