I want to buy the nikon d7000 and the tamron 18-270 lens.good idea?

I'm upgrading from the nikon d50 to the d7000… Can i use the d50 lens 18-55mm on the d7000 body and just purchase the tamron 18-270 lens?

Added (1). Wow… Thanks for all the great answer… Should i just stick with their original 18-105 lens that comes with the d7000?

Nice camera with 3rd Party lens? Not a good idea.

You'd be better off at the same budget with a D90 or D5100 and the Nikkor 18-200mm if you really want a superzoom lens.

Tamron makes a very nice 17-50mm and the 90mm macro is said to be good as well, but other than that they're not the lens maker of my choice.

Have you considered a two lens solution? The Nikkor 55-300mm VR in addition to your 18-55mm one?

Depends on what you want. An 18-270 is the ultimate lens in versatility but it's not going to push the D7000 anywhere near it's limits.

I'd keep the 18-55 for now and start saving for a nikon 16-85 or pick up a used 18-135.

The selling point of all the superzooms is convenience. With one lens, you can cover most situations from wide angle to telephoto. For travelling light and not carrying a bag full of lenses around, they can't be beat.

If you can live with the limitations of such a lens (including the Nikon 18-200) then it is a good choice for a one-lens-fits-all solution. It won't have the same image quality as a bag full of fast primes and high-end zooms, but you also don't have to carry all that stuff around. There are times when I carry that bag of stuff, and times when I just use one lens and leave all the other stuff behind. It really depends on what you need to the lens to do for you.

The versatility of the 18-270mm is attractive, but ultrazoom lenses generally have compromises in image quality, and I don't think that the Tamron has the greatest reputation among the ultrazooms. When viewed at 100% the D7000's 16 megapixels will magnify deficiencies more than the D50's 6 megapixels. The 18-55mm is reputed to have pretty good sharpness. The D7000 will probably reveal some limitations, but probably not too badly. The 18-105mm will give you more versatility than the 18-55mm, and reviews show it has sharpness as good or better. It has more distortion. It has more chromatic aberration, which is why it was introduced with the D90 which introduced processor correction. You get a best price on the 18-105mm if you buy it as a kit with the D7000.
If you really want a superzoom, the Nikon 18-200mm VR II is reputed to be the best.