I had used my 24-105 on a Rebel XT for awhile. I was happy with it. It didn't go very wide, but I had a separate wide angle zoom... Before that I had a 28-135mm, and I'd have problems with group shots if I didn't have the space. Otherwise, at the time, I was heavily medium to telephoto-oriented, so it got me by.


When I finally put it on a full frame camera, my initial disappointment was seeing the vignetting at 24mm, butaccepting that fact, I'm happier with it on a full frame camera.


From a performance standpoint, if you're willing to give up the 'L' classification, I'd lean towards the 17-55 f/2.8 IS. I bought the 24-105 in part becauseof future full-frame compatibility, and partly because I had purchased a 16-35 f/2.8L, which got me hooked on the feel of the L zooms. They're just fun to hold and twist.