PC is the most versatile system and I would always use it over a console (I even use it instead of my SNES since I found some good controllers.
Consoles do have their place though. They are the best for playing games with local friends (Smash bros on Cube cannot be denied for how fun it is, nor Halo on the X). I like consoles. I only dislike it when games are prioritized for them and them crappy ports made for the PC, or grossly delayed ones (*cough* Halo).
Xbox has lots more power than PS2 or especially Gamecube. It has a controller that actually handles FPS games well (which is why Halo is so fun). Its no match for the mouse's finesse, speed, and accuracy of course, but still works well for a controller. (I played MOH:AA multiplay for Cube and mAN!!! what a horrible controller (I'm speaking in general as well).
Xbox has twice the ram of PS2 and therefore can handle higher quality/more textures as well as process more complex games with higher numbers of objects/polys in the world and handling multiple windows the best. Also you have the nice big hard drive vs. horrible memory cards.
If I were to get a console it would definately be an Xbox (which is really just a simplified PC).
are you guys using an xbox to make these posts or something? the best moh game out in existence runs on the machine you are using to make your post. you cant compare a ps2 or an xbox to a PC.