It's simply that games thought for PC are better played on PC and console games are better on consoles, keyboard and mouse affect gameplay, and the same do gamepads. I think in the end it's a very subjective thing, but backed by matter of fact: if you like PC games no other platform will be as much good to play them.
That's why as a PC gamer I'm so tempted by Wii: it's so different that a comparison wouldn't make sense, I feel it would add new things I could like and very little comparable to the games I already play on PC, and so neither of them would risk spoiling the other.







