for a canon, cheap but good, does such a thing exsist?
Depends on your definition of cheap, but this is a very good lens for the money
http://www.onestop-digital.com/catalog/product_info.php?manufacturers_id=12&products_id=130
Sigma 10-20mm f/4-5.6 EX DC HSM
I've got the Nikon mount Sigma 17-35 and it's grand for the money - well made, relatively fast and my one is tack-sharp. They do a Canon mount too - have a hunt around and you can pick one up relatively cheaply (mine was a Jessops offer - something like £120 new which is a BIG reduction on RRP)...
Not sure it's wide enough though?
The sigma is an exceptional lens. It just keeps going up in price though.
I have the Sigma 10-20mm for my Nikon, but it is available in Canon fit too.
This lens always crops up when folk talk about wide angles because it is good quality and cheap. Well.. "cheap" relatively speaking.. it's £400, but there isn't much cheaper at that range. 🙂