thecoolcutter: Tamron makes cheaper versions of that lens.
The Canon 17-55 f/2.8 and 24-70 f/2.8 are both 'L' lenses, so you'll spend close to $1000 each if you get the Canon brands.
The Tamron versions are both ~half that price. I have the Tamron 17-50 f/2.8 and will vouch for its quality. It does sometimes hunt a bit in very low light... but that is partly because I am using a Rebel