Hey guys, I'm considering purchasing a better lens for my Canon, and I'm hoping that some of you could clarify for me. I've been shooting with the lens that came with my XTi for about a year now, and have decided that it's time to upgrade. I've been to several different stores in my area, and gotten several different suggestions. I liked the looks of the Canon 17-85mm f4-5.6 IS USM for the decent zoom it possess', without losing the closer focal length that I'm used of having. It also has the IS function, which I know is supposed to help reduce shake on longer exposures, which is also something I would love to have. However, I saw no difference when trying it out in the store (even though that probably didn't do the IS justice) at a slower exposure. Upon visiting another business in the area, I spoke to a man who was considerably more helpful and seemed to be more photographically-savvy. He informed me that lenses with IS tend to be quite fragile and has heard of several cases when a minor bump to the lens has completely disabled the IS. The same guy told me that he has found Nikon lenses to produce sharper images than Canon models, and recommended purchasing an attachment which allows me to use a Nikon lens on my Canon body. He also recommended another place in the area which sells worthy used equipment for a lower price than what I could get in most stores, or even to try ebay. I'd just like to get a second, third and fourth opinion about the usefulness of having IS and whether I should consider going with a different brand of lens aside from Canon, before making such a high-priced investment. Also if anyone has experience with buying lenses from ebay, or used equipment in general. I'm open to any suggestions, thanks!