In my opinion its really weird to see people telling a guy with a gtx 680 and an i7 that he is going to have a better time gaming on a xbox.
LOL, graphical quality is crap on an xbox, AI and physics are stunted, and there are a lot more whiny kids on xbox. Much as people say that gameplay defines the experience rather than graphics many xbox games exist also for the pc, sure they may only be console ports but you have access to the same games. There are xbox exclusives, but then there are also pc exclusives. You have a closed platform, no mods, and much less control over the device.
Some games play better with a mouse and you can always plug in a xbox controller if you desire.
Why would the op buy a top on the line imac if he is also getting an xbox to game on?
Gelite55: A 3970 is absolutely worthless for just gaming. An i5 will have no problems with all games as pretty much all games do not use more than 4 threads (for the few that do, i7 is fine). The cost to benefit ratio is crap for the 39xx series CPU's and only worth it if you are planning to use three gpus because of greater bandwidth. 39xx series cpus are intended primarily for professional applications.
OP: Does your computer do everything you need it to do? Does it have any problems?
If not, then ignore all comments saying that pc's are full of problems.
Are you 100% satisfied with your current pc? What exactly would an imac bring to the table and is it worth the net cost and time of the exchange?
Judging buy the amount of storage you have an imac may be a problem (also blu-ray).