I know this is crazy but....
The D800 is a monster. Huge files and heavy( w/battery grip ). So as an everyday camera for jobs, I love my D700 and my Pentax K-01. I basically consider my D800 as a medium format and shoot very few frames with it. The D700 is perfect for everyday assignments, portraits, onset,fashion, lifestyle, or whatever I shoot. It creates amazing images for all my clients and I have yet to hear anyone complain about the 12mp files I am handing them. Plus I have been able to blow up beautiful images with just those amazing 12mp.
So I know I should shoot my D800 all the time...but the D700 is really my camera of choice. And as for a walk around camera, that K-01 is perfect!