CONFUSED!!! help... which wide angle???

Hi, I'm a graduate student and an intermediate photographer looking to expand my lens collection, mostly so I can 1) continue to bask in the joy of taking beautiful pictures; and 2)begin making a little extra money doing event photography for my academic department and whatnot. For my Digital Rebel, I currently have the 50mm 1.8 II, the 70-200mm 2.8L (my pride and joy, a joint birthday gift from everyone who loves me), and the relatively weak 18-55mm kit lens that came with my camera. I'm looking for a good wide lens, but am having trouble sorting through all the options. Obviously, price is a factor, but I know I'll have the lens forever, and want quality. I've heard some things about the 16-35 L lens that are making me think it might not be worth the money. I'm open to anything anyone might suggest: from a prime to something other than Canon.

THANK YOU so much for your help.

The Canon 17-40 f/4L is a very good lens and the cost is resonable, unless you need a faster lens. The 16-35 f/2.8L replaced the 17-35 f/2.8L, and from what I have heard the 17-35 may be slightly better, but only in a measurebater sense. I have seen some really good results from the new EF-S 17-85 IS, maybe not "L" but certainly very good. The 3rd party offerings generally don't hold up to "L" quality but do very well. In the end I would research these lenses on the net, using sites like
The Luminous Landscape
DP review
Photodo