All-around lens for Canon (17-85 Canon or 18-125 Sigma?)

Joined: 25 Oct 2004 Posts: 32 Location: Baltimore, MD

I have a Rebel XTI, and I am tired of changing between my 18-55 and 70-300 lenses. Also, I find that I often want to shoot something in that 55-70 range that I am missing.

So, I am looking for a lens that:
- Has good (not necessarily great) optics
- Includes at least 18-70mm
- Is image stabilized
- Has a high-speed motor
- Is less than $500

I've been looking at these two lenses in particular. The Canon has generally good reviews; although many reviewers say that it is soft and has some color problems at shorter focal lengths. I cannot find any reviews on the Sigma.

- The Sigma 18-125mm F3.8-5.6 DC OS HSM http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3342&navigator=6

- The Canon EF-S 17-85MM f4-5.6 IS USM http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=149&modelid=10511#ModelFeaturesAct