I just traded in my 2011 MacBook Air for the new 2012 MacBook Air for the faster speed and 8gb ram. ...
After reading about the new MacbookPro Retina and seeing one yesterday in person, I was thinking that with 16gb ram and a fast SSD, I could use this to replace my aging MacPro ... It probably would never leave my home once I set it up.
My reply is probably too late, but if the proposed computer is not going to travel, why not get something like a 27" iMac for less?
Besides portability, the only gap I see with the current iMac models is USB 3, so maybe waiting for the high end iMacs to get USB 3 will make them even more viable as alternatives to the Mac Pro.