I used to have the 17-85 but sold it. I now have sigma 10-20 and 24-105 L.
The 17-85 is very versatile as it can do wide angle and has a bit of reach compared to other lenses of its kind. It has IS too which is very handy. If you get a good copy of this lens, keep it, its handy to use when you only want to carry only 1 lens when you travel.