Oops, actually I only mentioned the Pentax in passing (and I suspect the new Canon 400D will outclass in every single respect anyway) , the D50 is much superior in terms of noise and retains a lot more detail at all ISO's! I wouldn't go higher than 6mp for night photography, the trade off isn't worth the marginal increase in print size, so the D50 would be the one I would pick hands down.
Luckily none of my Nikons have ever needed a trip to the repair shop so far, except when I cracked my LCD on the D200 with the spike of my monopod... In fairness to Nikon, at the time of the F1 it was the pro's SLR of choice and took a much heavier beating than most cameras could expect!