Well, the Nikon D700 is comparably priced to the 5DMkII, so I wouldn't say that price should be an issue if you are looking for Full Frame. The 5DMkII does have video while the D700 does not.
And I don't personally believe that Full Frame is necessarily better than crop frame, it really depends on what you plan to do with your camera. I do mostly sports with medium to long telephotos, so the crop sensor gives me more "reach". Try to find an affordable 300mm F2.8 lens (the top end "equivalent" focal length of my 70-200 F2.8 on the D300.)
I went with the D300 because I liked the build quality, and the ergonomics are better in my opinion with respect to the control dials. I don't like the rear dial on the Canons. Generally speaking though, the Canons and Nikons are really neck-and-neck. Canon top-end glass is slightly more affordable than Nikon's equivalent, which makes me sad. Oh, and Canon runs the occasional rebate, making the price advantage more pronounced.
But, that is just something that a company in the #2 position in the market does to try and get more market share!!
