Gawd! Just imagine the muscles one could develop tipping and swaying a 27" iMac around..!
I can see that becoming a new national sport.
The only reason to pick up a PC is for Valve's games (which are far from needing demanding hardware) or if you are a fan of the RTS genre. Every other PC game in the last decade has been a port from consoles.
This claim, and the truth, are so far apart that it would take you years to drive from one to the other.
--Eric