Then look at the Nikon D90 or D5000. The choice would be dependent on your lenses that you have now(whether you want to save the extra money to buy a new lens). I'd go with the D90 just for the bigger and brighter viewfinder but that might not mean much to you. It's personal preferences.
One other thing you should think about is whether you'd be better just to spend that money on better lenses. You didn't say what lens you have, but if their just the kit lens and one other low budget lens then I'd say that you'd do better to invest in lens and worry about the body later.
I bought a Nikon D40 when I started photography classes in college. It was all I could afford at the time and now I'm wanting to move up to something with maybe a litle more ISO range/shutter range. I know the D40 is a base model but I really don't know what would be best to move up to? I'm looking at about a $7-900 range.
I have a side business that is just part time at the moment and I focus mainly on families and pets. I try to use as much natural light as possible and for some reason I just hate artificial light sources, if this helps any.
I appreciate any help!