Great stuff mate, thanks for that.
I'm a bit dull with games and mainly only play FIFA, the odd racing game, and GTA. I was just thinking of getting some more use out of it really, considering it cost me £1250. Plus, I can't afford to get a next gen console and thought that my Mac would be similar(?) to the next gens in terms of power and all that (I might be way off, though). Games seem to be a fair bit cheaper on PC/Mac too which would be nice. Plus, the retina display is absolutely superb. Much, much better than my TV!
I've seen that you can plug an Xbox controller in to it, which would suit me perfectly.
I'll check Steam out this weekend and have a little browse.