I'm going to make a Canon recommendation, not because I think it's better than Nikon but because I'm more familiar with the Canon lenses.
EOS 50D with the 17-85mm IS USM zoom (do not get the standard 18-55 kit lens). Around $1500.
2807B012 Canon EOS 50D Digital SLR Camera Body Kit, 15.1 Megapixels, Black with EF-S 17-85mm f/4-5.6 USM Image Stabilized Lens - USA Warranty
Add one of the 4 available 70-200 L tele-zoom's later and you are golden.
If you are interested in HD video then the new Rebel T1i is an option as well. Same lens reco applies.