To offer a view I haven't seen in the thread (haven't read all pages though), I just plain like controllers. I like that each console has its own controller and that this influences the games directly. I'm perfectly fine with keyboards and mouse, they're perfect for RTS games (one of my top favorite genres) and FPSs and what not, but since all PC games have to take into account this same type of control (even if they also support optional stuff like wheels, etc), many times games end up feeling like they all control the same.
Obviously this point relates stronger to Nintendo's consoles than Microsoft's or Sony's (the latter who basically use the same controller for over 10 years...). Nintendo designs its controllers thinking about the type of games they want to do and I do believe this helps bringing out more creativity in them. From the Game & Watch, to the NES, to all their other consoles and handhelds, this has been true. The controller they designed is definitely part of the reason why Super Mario Bros or Mario 64 or Metroid Prime or Smash Bros or Wii Sports or Brain Age or Metroid Other M are the games they are and I really like the diversity this brings to the table. I find it fascinating, actually, to think how much less interesting Nintendo's games in general would be if they just kept the SNES controller around and added two analog sticks in it. I don't get that much of that kind synergy between controller/game in PC games. Maybe I haven't played enough, though.
To offer a non-Nintendo example, I'm sure Shadow of the Colossus would be a rather different game in case it used a keyboard for movement input instead of the analog stick. And I don't think it would be for the best.
The other reasons people have talked about in depth. PC doesn't have many of the exclusive games I like and the ease of use of consoles is definitely preferable. I remember buying Battle For Middle Earth a few years back and I had to mess with register files in order to be able to play online. I spent as much time researching what the hell was wrong with the game as I did playing it on the day I bought it. Screw that. I'd rather actually play games, you know.
That said, I will occasionally put up with the PC's particularities when I have a big enough incentive, like I did for Starcraft 2 for example.