I'm sure it has been asked a lot of times, and I apologize in advance if this is a tiring question already 
I'm considering an ultra-wide lens (I consider Canon 17-40L to be wide but maybe not ultra-super-wide?), and am leaning towards Tokina 12-24mm (after reading many, many reviews on Sigma, Tamron and Canon 10-22mm), since it seems that it delivers the best bang for the buck with considerable quality in par with the others.
The Toki 11-16mm is nice and faster (and a little more expensive), but I'm seeing image results from Pixel Peeper, and I want something a little bit more versatile than those I saw.
My friends have tried to convince me to buy the 17-40L instead, but I do want to have something wider than 17mm. Plus it's on the higher end, in terms of price.
My current list:
Canon XSI/450D
Kit Lens 18-55mm
Sigma 18-125mm DC OS
Canon 50mm f/1.8
Do you think I should get 17-40 instead of the Toki?


