I'd get the D200 then
It takes CF cards and blows away the Canon competition (Easily beats 30D and the build quality but not IQ is better than 5D)
As for 400D vs D80, the D80 is solid, and it's more expensive for a reason, it's a better camera.
The IQ difference between D80 and 400D is negligible now it's no longer a factor, high ISO performance is pretty much the same for both cameras, the difference is in camera processing.
If you look at the RAW captures in detail they are the same, the same detail is captured but the Canon has better in camera processing, thus with Neat Image or Noise Ninja and the Nikon you can get superior results as the Nikons tend to expose for shadows which don't cause any problems with clipping highlights.
Of course the Nikon speedlight system is much better than Canon too
If you are on a budget you can look at A-100 Sony aswell, but I wouldn't recommend it.
For entry level you can seriously consider getting a D70s, it can produce superb pictures, it was my previous camera before I got this D200.
Canon is only worth buying if you are getting 1D and a full set of USM IS L lenses, other than thier lower and mid range cams are like plastic toys.
Go for Nikon you won't regret it.