28 135 Is ?? Have you considered the 28 - 135 IS. It should give you about the same range as your existing gear and it is $420 at B & H. It is part of the Canon rebate scheme as well.
I hadn't because with the 1.6x crop that makes it ~45-216 - not quite wide enough on the XT. The 17-85 is almost exactly 28-135 with the crop factor thrown in. I don't think I can get my current range with decent quality in a single lens. I'm also open to suggestions for non-Canon lenses.