Before you go even thinking about a 24" Imac, theer has been quite a few people reporting problems/not happy with calibrating the Screen, I looked at one the other day, and the screen has or seems to have a glass front on it??
I think if I got another mac, it would not be an imac, (I have a 20" version, seems pretty good, and of late looking to add 2nd monitor, and another gig mem), but a mac that has a separate display that you can choose for your self.
Personally (lets assume they do sort out AF on MK3) go for a MK 3 being 10MP it is no a great strain on any PC/Mac,,,,,,, get better images first
, then worry about PP on them 
1D Mark III




