I voted D40x because I think Nikon is the superior system(for now) if money is not an issue. If it is, the Sony has a more complete package if you are keeping the kit lens.
A100 has to much noise at high ISO's.
D40, 350D, D40x, 400D, D80, 40D, D200, D2X, D300, 5D, 1DsIII, D3, 1DIII
I think its interesting how you have placed the 1Ds before the 1D. Don't get me wrong, I'm not saying what you've said is incorrect but I've always assumed that the 1Ds was positioned above the 1D because of it's higher pricing. I suppose it depends on how much you value megapixels and sensor size over speed.