I also was just looking at this issue recently. I read some of Bryan's reviews and before you jump to purchasing the 17-55 2.8, check out his reviews. I saw a Tamron lens that I believe was 17-50 f2.8 that looked pretty good. Sure it isn't Canon, but from what he said, it appears to be pretty sharp also. Plus it is about $350. I haven't owned or purchased any of these lenses, so take my thoughts with a grain of salt.