in honesty, canon has more affordable offerings.
i believe that if you go nikon, most people will be forced to go take up the 24-70mm f2.8 and the long range lens 70-200 f2.8 VR. i think the same thing for nikon wide angle - f2.8
for canon, there is a cheaper option of buying the f4 trinity lens - 17-40 f4, 24-105 f4 and 70-200 f4 (w/IS) which delivers 'pro' quality (definition of their L lens range).
that is the major complaint on nikon - lack of a cheaper fixed f-stop variable focal length lens.
if you buy D700, i think u would expect to pay in the 6.5-7k range for a nice kit ie w/24-70 f2.8. canon u can probably get away with around 5k or less w/ 24-105 f4. this price difference can be a major consideration for people moving up from a crop set-up with EF-S or DX lenses.
but ofc if your poison are primes, then there is almost no diff in offering.
however, if you already have a stable of nikon primes, i dont think there is a point switching to the 5D2. i bet nikon will throw their own HD video FF into the fray soon. in any case, the D700 is also a very good body and better AF system than 5D2.