Depending on what your looking to spend, you may want to wait for the Nikon D90 to come out. Its about $1200 but it also does video at 720p. For a good photo reference camera, any entry level dSLR will do it. Canon has some good entry level ones. The better Nikon dSLRs have really good low light performance in the D90, D700, and D3 models.
For the best color taking bracketed exposures and creating HDR images will help you get the most dynamic range in color. Most dSLRs will do that.
Personally I have a 6.1 Megapixel Nikon D50 and it works well, Im either going to upgrade to the D90 for video or wait for Red’s Scarlet.