I'd like to get some opinions on which Nikon compatible DSLR zoom lens seems to be the best on a $500 or less budget starting at 18mm - Obviously the 18-200 VR is ideal but hard to find and more than I wish to spend. Is the Nikon 18-135mm the best or a Tamrom, Sigma?

Thanks

probably better asked in the nikon forum but Ill play. The tokina 12-24 is almost legendary and rivals the nikkor 12-24 at half the price.

Tamron's 17-50 is superb also at less than half the cost of the nikkor 17-55. Build quality is spotty so watch for that.

The Sigma 17-50mm 2.8 is an excellent lens, and according to Pop Photo reviews it rivals Nikon's Pro 17-55mm 2.8. I purchased the Sigma for 1/3 of the price and I'm very happy so far.