I'm a photographer and my 2006 20" iMac desperately needs to be replaced. I can't decide between the 27" iMac or a 15" rMBP. The main worry I have is that the screen size of the rMBP would be too small to do any serious photo editing with. I realize that I can buy an 27" Thunderbolt display but I really don't want to spend more than $3000. Suppose I could always get one later though. Anyone here do a lot of work with Photoshop & Lightroom on their 15" rMBP's? If so, how do you like it?