Sony makes a nice FF product, and so does Canon, but I went with the D700. So far it's been a wonderful handling camera that I enjoy using. The high ISO performance is satisfying...although fast glass and low ISO's provide even better DR and richness.
@ Nostatic - I would like to see a line of F4 zooms from Nikon too. I think every Nikon user would honestly
In the meantime, I'm happy with the 18-35, 50/1.8, and 85/1.4.
I haven't decided what to do with my Pentax equipment yet. Most of the AF stuff is gone, but I have a hard time selling my Taks or K20D as I can afford to keep it. I suppose I'll evaluate like Samsungian and see if I use my Pentax gear enough.
I also think it's odd the way people act when they change systems. Ultimately it's just a camera, a tool to be used like anything else. Pick the appropriate tool for the job. That's it.