It will be my main camera soon but I'll keep my Canon 5D2 as reserve. The Fuji is excellent as far as I can see after an extended play this weekend but the lens range is obviously small (if growing). I'll keep my speciality lenses (85/1.2, 24/1.4) on the 5D2 but get a 35mm (=50mm) and probably the 60 macro (=90ish) to replace the Canon equivalents I have, plus sell my 70-200 zoom to fund the new body.
I don't think the fuji is any better than the 5D2 so won't be any better that a D700. You will notice a clear drop in AF performance even with the new firmware but strangely, though a sometimes dodgy AF bugs me on the 5D2, it doesn't on the Fuji. I think lust/GAS is making me blind to its faults! But the IQ is fine and the small size is a bonus.