Assuming you were looking for some actual guideance rather than me
being a wiseguy,
Currently, I'd get a D70, non S kit. I prefer the ergonomics and
usability of the Nikons to the canons, the Olympus 4:3 aspect ratio
bugs me (I don't want to crop every pic for 4x6s), the 500 bucks
won't buy any more performance for the prosumer, and I don't know
anything about the Minolta.
Why the 70 over the 50? The kit lens with the D50 is pretty
underwhelming by many accounts, whereas the kit for the d70 is
nice. Many folks are getting the D70 kit lens with the d50. THat
said, right now there is a rebate on the D70 non s, and it is
actually cheaper to get the D70 kit than the d50 with the 18-70.
Nothing wrong with the d50, but the only advantage over the d70 is
noise, and I've yet to see any evidence that this is anything but
different in camera processing that could be duplicated in post.
The d50 lacks features I use (2nd command wheel, backlit Lcd) so
for me, the choice is easy.