nikon
konica minota is good too. for $500-800 i'm sure you can find a decent lower end SLR camera somewhere..I was thinking a nikon d50, but they're msrp is $899 :|
if you like a nice camera, a little on the bulky side, canon powershot "S2 IS" is very flexible, downside is it doesn't do iso800.
might want to save up maybe for a nice SLR, either nikon d50 or canon rebel xt..I believe you'll never regret buying an SLR if you do!