I honestly wouldn't know these pictures from a D700 or a D40, all thing equal. Not a knock against you photographs, but unless you're delving into 3200+, I don't think there's a huge difference in new cameras.
I concur. As a former Nikon user who recently switched, the pictures in all honestly look very P&S (not being rude, so I apologize in advance for being a little strong in my statement). If you go onto NikonCafe (my former playground) you can find thousands of D700 pictures, a very high percentage of which are not IMHO very impressive from a color and detail standpoint. The D200 which I recently replaced delivered a better image @ base ISO (but was horrible at high ISO). I think the D200/D2X were among the best Nikon's at low ISO, but the new tech just doesn't impress me.
Nikon's newer EXPEED processor and CMOS sensor produce rather soft looking images with a very artificial color palette, one reason I left the Nikon camp.