After a suggestion by a faculty member, I am considering the Canon EF 17-40mm L wide-angle lens. Pricing is quite varied:
The reviews are very favourable, as is the comparison with the Canon 16-35mm f/2.8L (twice the price for twice the light). The primary advantage over the 24-70mm f/2.8L is the weight (approx. half) and the wider angle.
He also suggested that I could likely negotiate it down to $700, or if I waited until Boxing Day, I could avoid the sales taxes. My lack of people skills make negotiations impossible and I have a low tolerance for shopping-frenzy crowds.
I am hesitating on the purchase because I prefer a versatile lens— usable both indoors (meaning faster than f/4) and outdoors and I prefer a prime (less glass means more light). Canon's wide-angle prime lenses, however, are quite "sucky".
Update Sat Nov 22 16:15:07 2008: David responds with some suggestions:
What's your budget? Canon has a 24 mm f/1.4L for $1300, with a less expensive f/2.8 at $500. 28mm f/1.8 and f/2.8 can be had for $600 and $300. I don't see the half-stop going from 1.8 to 1.4 being worth $700 IMHO.
Gruber shoots (only) with 50mm and 28mm, both f/1.8.
Note that once you get into the f/3.5 range getting any kind of bokeh is difficult at these focal lengths. You probably want to stay below f/ 2.8 if you want any meaningful blur.
Remember that you'll replace your body before you replace your lens, and if you ever stop being interested in photography, lenses don't depreciate as much as bodies.
My budget is virtually unlimited, but at this early stage, I refuse to buy a lens that cost more then the body ($1400) just as a sanity check— I don't want to buy optically fantastic lenses that collect dust at home.
Eventually, I want a (indoor/outdoor) wide-angle lens (24mm or less), a 50mm (I'm happy with my f/1.4 USM) and an indoor sport lens— 85mm (f/1.8 or f/1.2L) or 100mm.