Wow... You use yours with 4 external screens and it handles it? That's insane. I was thinking, at the end of the day with today's specs, the iMac, really, is just a MacBook Pro with a dedicated 27" screen.
P.s. to Crazyeyes; you're 100% right, the Retina display MacBook Pro is far from worth it. As you said; no ethernet, no firewire, no CD ROM and to top things off, RAM that is soldered to the motherboard!
I think I'm gonna go the MacBook Pro and just get HQ external displays... If anyone begs to differ, by all means put your opinion forward