tinplater wrote:
Never used the 17-85, but have used and enjoyed the 15-85 and to a lesser extent the 18-135. The 15-85 is sharper, better build quality, and most importantly, faster. If I were to choose one of the three lenses it would be the 15-85 hands down (it is on my 70D right now).
Another vote for the 15-85. It's my go to lens on a 60D. You'd be surprised what a difference that extra 2mm at the wide end makes.