The whole console vs. PC thing is a personal thing. I can tweak my current hardware to get the best out of games, so I'll admit when I have the choice of platform, I'll normally go for PC, although lately I have picked console ore because my set-up is getting older every day, and it takes less tweaking to get something to run on a console.
As for Halo 3, I will get it eventually, probably when it's in a bargain bin or such like, as right now I'm still playing ES4: Oblivion on PC and a selection of other games on PC and console.