http://www.nikonchat.com/nikkor-lense-repair/

What are some good third party lenses that will not break the bank?
I recently bought a Nikon D40 SLR. The lens that came with broke. I want to upgrade instead of repair (no, not covered by anything, I've been there already), but I'm on a tight budget. What are some good lenses third person, and how to match the Nikkor? I especially portraits and landscape photography, many of them are subject nature. I'm looking for a good "walking" lens. What are your recommendations?
Ken Rockwell is not the best source of information, some cameras will be reviewed based on hearsay and media press, instead of actually handling the camera. Similarly, it is ridiculous to pooh-pooh third party lenses without really trying or use. First, the D40 only autofocus lens with a built-in motor lens, called the Nikon AF-S and Sigma HSM. At this time, Sigma and Nikon only these lenses, so limiting their options for auto focus there. The kit Nikon 18-55mm lens that comes with the D40 is quite affordable, about $ 120 from the http://www.bhphotovideo.com 18-70mm imported, is slightly more expensive at $ 279.00, but is cheaper than the U.S. officially imported version has a $ 349.00 Sigma 18-50mm HSM, two versions reality. Version 2.8 is $ 499. The wide opening makes this goal a little more attractive and news flash: this is an affordable alternative to the Nikon lens 17-55mm to break the bank at $ 1,200.00. The other 18-50mm Sigma is the most equivalent to the nikon kit lens and costs $ 139, it is f / 3.5 to 5.6. Based of this, your best bet is to get the Nikon 18-55mm $ 120 or the Nikon 18-70mm $ 279.00. The 18-70mm lens is a much, much better than the 18-55mm, so it could worth the extra money for you.