The 13" Pro can't be the perfect choice without discrete graphics. The Intel HD 4000 may be the best Intel graphics to date but a 4 megapixel display is going to bring that chip to its knees.
I'm itching to replace my MacBook Air with a machine that sports a Retina display, but as it stands I think I'll have to wait for the next generation with better performing graphics that can do the resolution justice.