Thats because you've got a 17-55mm. Haha. 24-105 isn't wide enough for 450D. My sig also has that.
GMAN
Yes. I agree that 24-105 is not wide enough on a 1.6x crop but it's an investment for FF upgrade later.
I might get the Tamron 17-50 instead of Canon 17-55 which is priced out of my budget. ;p