I had two D700s for work and consider them to be one of Nikon's classics.
But being so big and heavy I never took one out for pleasure - ever. Last year, a significant birthday and the fact that Fuji were practically giving away X Pro 1 kits I treated myself. My love for photography was rekindled!
I loved the X Pro 1 so much I decided to take a big gamble and bought a pair of XT1's for work. Whilst there are certain sacrifices, I would never go back to the big, noisy and intrusive big Nikons, wonderful as they are.
In fact I'm just processing a wedding right now where I had an assistant using D700s. The XT1 files are noticeably nicer all round (at least up to 1600 ISO). I feel that my decision has been further vindicated.
Lightweight, quiet, unobtrusive, beautiful prime lenses, intuitive to use - I'm a happy camper right now!