A good lens for street photography?

I have a Nikon D3000 but I'm going to upgrade to a D5100. I have been using the kit lens with my D3000 for a while but I'm thinking to get a wide angle lens. I love taking pictures on the streets of people, buildings, and other things that interests me. Any ideas on a good lens for under $400? Here are some of my photos, if any one cares.

I'm not sure about what a good lens would be for street photography (especially since all I use is a 17-85mm) but I will say I just had to add you on Flickr. I'm also from San Jose and I love seeing pics from that area since I no longer live there. I'll be commenting some time soon.

Any natural lense would be good. It might sound strange, but no animal sees with a 400 telephoto eye. A 50, good and if you like buildings a 35 or 28, maybe better.

I'd say its definitely got to be a lens with a wide angle, i don't see much street photography that uses a telephoto lens. But then it is handy to have that telephoto end on a zoom lens.

I too would say the 17-85mm. Or maybe buy a wide angle prime sigma lens.

Depends on what images you want to get really.

You can use any type of lense you want… Why restrict yourself to one lense? Google street photographers… The ones that do it for fun… And you will see that it doesn't matter what brand of camera you use, what type of lense you have… The main thing is to experiment and have fun.

Remember, "The best camera is the camera you have with you." - Chase Jarvis

Oh, one more thing… You "can" capture street photography images with a telephoto lense… It's been done many times and still is.