Honestly, I think both systems have their own respective strengths and weaknesses, which is why I've never been 100% PC gamer or 100% console gamer. I'm not much of an online gamer, so for PC I turn more to strategy games. In general I think PC games are more cerebral and more intelligent in their design. I enjoy the wider range of offerings on the PC. From mods, to indie games, to expansion packs, PC games go far beyond the traditional boxed retail copy and offer a much broader range of gaming experiences. And of course, I like the upgrade-ability and customize-ability of PC's.
I use consoles for more laid back gameplay. I play a lot of RPG's as well as action adventure games on consoles. I also play most of my shooters on a console (I know, no KBM, c'est travesty). I still play the big shooters, like HL2 and probably Crysis, on PC, but like I said I'm not much of an online gamer and I've long since become more than proficient with a game pad for controlling an FPS. So when given the option I prefer the laid back setting of my living room for that kind of single player experience.
Really, I've never much been into the whole console vs PC thing. I'll sway back and forth a little as different games come out for each respective platform, but I'll probably always play on both platforms.