The people who say that the 17-85 is similar to the kit are quite simply wrong. It is definitely superior to the kit. I used the 17-85mm for a few years, up until recently. It is definitely a capable lens, though it has many shortcomings. Just read up on the reviews to know where the weak spots are. I find that the focusing is fast and quiet. It has a good range while being extremely small and light. Picture quality is decent, though not great. However, I find the barrel distortion to be very pronounced. I need to use photoshop a lot to straighten the 'falling buildings', etc.
However, if you compare it with the 17-55, then it will pale quite significantly. The 17-55 is a great lens. It produces great IQ with fantastic colour. I cannot fault it in any sense. People do point out that the lens exhibit light falloff. However, that is the nature of all zoom lenses... even the greatest. I would even say that this is the best EF-S lens money can buy.
As for the lack of zoom range... you cannot have the best of both worlds. If you want quality pictures at constant wide aperture of f/2.8, you need to sacrifice some range. Else, the lens will become too big and heavy, even if it is scientifically possible to produce such a lens.
Personally, I think if you need the range at some point, you can pick up the EF-S 55-250 or the EF 70-300 to go with the 17-55 IS. The best would be the 70-200L IS, but that's considerably more pricey and also heavier.