I recently purchased a Nikon D40 after having it recommended to me by a friend. It's my first professional camera, my only other camera being a Canon Powershot A530.
The main reason I got this camera (other than to have a high-quality camera that could take extremely good pictures) was for concert photography. It's something I'd really like to get into, but I know that I'll need a certain kind of lens that allows for a very high shutter speed in such dim lighting. The camera came with a 18-55mm zoom lens, but I doubt that will work well at all.
As for my budget: I'm a teenager earning minimum wage, so anything over $300 is out of the question at this point.
And I'm a complete newbie to this, so any recommendations I can get would be amazing. Thanks.