Canon 18-55mm kit lens replacement

[brandonlau2]

I'm looking to get a replacement for my 18-55mm kit lens as I am finding that the image quality just isn't up to par anymore. I have just recently purchased a Canon 70-200mm F4L and am looking to get the Tokina 11-16mm F2.8, so I am looking for one last lens to fill in the range between those two.

A couple of lenses that I have been eyeing:

Canon EF-S 15-85mm f3.5-5.6 IS USM - I've heard that the image quality for this lens is pretty great, and the range would perfectly cover the gap that I'm missing. The only drawback for me is the price; retailing for around CAD$800, I'm wondering if I should just go for my other choice...

Canon EF-S 17-55mm F2.8 IS USM - while slightly more expensive, I've heard that this lens has the same image and build quality as an L-series lens. The constant F2.8 aperture would be a great bonus as I do quite a bit of shooting in low-light, an area where I've found the kit lens to be severely lacking. I should be able to find this lens used for around the same price as a brand new 15-85mm.

I was also looking at the Canon EF-S 18-135mm F3.5-5.6mm IS, but am feeling a little dubious as to whether it would be a significant upgrade over the kit lens in terms of image quality. It does have some great plusses going for it though, including the wide zoom range and of course, the price.

Any thoughts, comments, and suggestions for other lenses would be much appreciated! I do not necessarily have to get a Canon-branded lens, it's just that I'm not as familiar with the other manufacturers.

[Elmo]

17-55 f:2.8 Tamron