Battle of the super wides

Hi all,
I'm currently shooting with a Canon 70-200 on a 20D, and a Canon 17-55 on a 30D and am looking at adding a super wide for some SFX shots and such. I've had luck with Tamron in the past (I have one of their 18-250s and love it) but am wondering at which of these three lenses would be best:

Canon 10-22
Sigma 10-20
Tamron 11-18

I would like to get the Canon, but I don't think I would use it enough to justify the price. Anyone who has pictures and/or stories of their experiences with these three lenses would be great. I've also been looking for reviews of them if anyone knows of any good ones.

Thanks!

Lightrules had a nice test at his Pbase site comparing the 10-20 and the 10-22. Just do a search on google for "lightrules lens tests". When I decide to purchase a wide angle, it will be the Sigma 10-20. I don't see enough difference in IQ to justify a $230 price difference.

Consider the Tokina 12-24 instead of the Tamron 11-18 on your list. The Canon 10-22, Sigma 10-20, and Tokina 12-24 are all elite class lenses, with superior optics. The Tamron is pretty weak overall compared to the other three.

I love the 10-22. I use it a LOT.
Once you start using it, you might find yourself using it a lot more than you thought. That's what happened to me.

Haven't owned any of the other lenses but you'll likely be very pleased with the canon.

I bought the Canon 10-22mm a few days after reading a lot of reviews and comparing shots all over the internet. The jist of what I read was that most people who compared the lenses felt the non-Canons had more distortion at the wide ends, and the images were a little softer wide open than they'd like (especially on the Sigma). Also, the Canon gives you a little wider aperature. With the price difference now being only about $100-$150 (I bought mine for $615), I decided not to risk it and chose the Canon.

I would recommend you look at the Sigma 10-20 and Tokina 12-24. If 12mm is sufficiently wide for you, the Tokina is a real gem.