Mastering Wide-Angle
Instapundit has a pointer to this article by Petteri Sulonen, Mastering Wide-Angle, which is a discussion on the pros and cons of wide-angle photography, and where and how one would use such lenses.
I’ve also heard wide-angle lenses called “story-telling lenses” (was it in Understanding Exposure?), as the photographer can capture a large amount of scenery and create a bit of narrative or at least the sense of a moment in a narrative. The article does point out that one can do portraits with wide-angle lenses, but the subject will tend to have to be an element in the scenery rather than the subject of a traditional portrait. His example of a guy working with hay illustrates both these notions: the man is only in a part of the overall shot, and he’s doing something.
The widest angle I have is on the D70 kit 18-70 lens. The 12-24 should give 50% more angle (on the D70, it should (perhaps ironically) be equivalent to a 35mm film’s 18-36), but is pricey. The Sulonen article does have a list of alternatives, such as the Sigma 12-24mm/4.5-5.6, which is cheaper, but still in the $500+ range.