Go for it. I'm HUGE on Nikon stuff, and you could probably make 800+ dollars by selling those two cams, setting you within reach for a D300 with a little more saving, or buy one used with low shutter count for around 1000.
the High ISO capability of that camera is STUNNING. also it feels very good in the hands. its essentially the same camera as the D3, with the few differences coming from making the D3 just a little bit faster, a little bit more comfortable; things that you would pay off if you shot for a living, but that you wont mind missing if your only an enthusiast/ semi pro.