I dont recommend the 17-85. I thought it would be ideal for me, but it's v.poor in comparison to the 17-55. Not v.sharp, build quality is not so good, the zoom extends when the lens points down and the pics just aren't as impressive (though it is a nice step up from the stock 18-55).
The 17-55 rocks! If you can, save up for another month - it'll be worth it!!!
I agree that the 17-55 is an L lens in all but name but I suspect you may have had a poor copy of the 17- 85. My zoom stays where it is whichever way the lens is pointing (1 year on)
The 17-55 costs
at least £250 more and is made of L grade glass , it should be a better lens for that difference in £ ( enough to get a Sigma 17-70)
However this does not make the 17-85 a poor lens at all (IMO) .
I'm not recomending it as such ( I like it and I'm keeping mine anyhow ), It may not be perfect but it isn't anywhere near as poor as some reviews would suggest in day to day use
I find that its Build quality is actually quite good , Sharpness wide open is Ok centrally though it is somewhat soft at the edges but from 24-75mm sharpness is generally quite fine.
Barrel distortion at 17mm is marked but nothing PS cannot correct.
Together with second generation IS and ring type USM ( Fast quiet accurate AF with FTM focusing) I would say It is rather
more than a step up from the kit lens
and
It is possible to get quite sharp images with it, more so with the 30D . I had the 17 -40 L ( Lovely lens that) which has since been stolen , and also a 50mm 1.4 ( amongst others) but I would not say the 17-85 was rubbish next to them.
Certainly If you can afford the 17-55 it is the better lens. If not, ( like with all kit), you can learn to work around the limitations of the 17-85 . I think if one is not Pro and making prints the size of billboards, we can get too involved about sharpness ,AF accuracy ect of these "consumer grade" lenses
This review is a very accurate one and reflects my experience with it
http://www.bobatkins.com/photography/reviews/ef-s_17-85_review.html
This is a comparison .. of sorts
http://users.cybercity.dk/~nmb1805/lens_comparision/