Canon EF-S 17-85mm f/4-5.6 IS USM

Good points
Flexible 5x optical zoom ratio
Effective Image Stabilisation
Fast and quiet USM focussing motor
Polariser-friendly internal focussing

Bad points
Visible light fall-off and softening in corners
Relatively expensive for specification
Lens hood not included
Only compatible with EF-S bodies

Canon EF-S 17-55mm f/2.8 IS USM

Good points
Bright f2.8 aperture throughout zoom range
Effective Image Stabilisation
Fast and quiet USM focusing motor
Superb low-light performance

Bad points
Relatively expensive
Construction not 'L' standard despite price
Range shorter than cheaper EF-S 17-85mm
Lens hood not included

Canon EF 17-40mm f/4L USM

Good points
Canon 'L' build and optical quality
Fast and quiet USM focusing motor
Constant f4 aperture throughout range
Will also work on full-frame body

Bad points
Shorter zoom range than kit lens
No IS (although not particularly necessary)
Overkill if not considering full-frame in future