The lenses are similar optically, with the Nikon maybe having a slight edge. You will probably be able to buy the D80 with its kit lens cheaper than buying the body and lens separately. If you want 3rd party, I'd go for the Tamron. I have a couple of Tamron lenses, one in particular is a pretty good performer (especially for the price) I have the D80 with the 18-135. I am pleased with the lens for travel and walk-around use. It does suffer from some distortion in the widest range, but that is true about any super-zoom, so you won't want to use it for architectural work, but for vacation or shots of the kids, it is a decent lens.