This is one of the optional kit lenses for the 20D/30D & 40D cameras. As a non 'L' lens it is very good, and is excellent value (especially if bought as part of a kit with a body). Until the end of June 2008, Canon have a £40 rebate on this lens (you must provide the bar-code, and receipt) so double check with your retailer.
Compared to the 18-55mm that many of the range come with, this is massive, but it's a reasonable size and weight for what it does. The optical image stabilisation works well, and it covers a good range of focal lengths (27mm to 136mm equivalent field of view). The front element doesn't rotate during focussing or zooming, and the recommended hood (the EW-73B) is a petal type that can be stored back to front on the lens.
Summary: While optically not quite as good as the 17-40mm F4L or 24-105mm F4 L lenses, it is a fraction of the price (and weight) of either.
This is probably the basic lens for the EOS camera but now that it comes with the image stablisation it is actually a big step up. The 17-85mm lens basically offers you all you need for your basic photography from potraits to lanscape shots. So I suppose it is a good lens to have on the camera in case a shot does turn up, as it is not to big or bulky to carry around all day. If you are only after one lens to start with, I would highly reccomend this option.
This is the obvious lens to go for on all Canon 300d, 350d, 400d, 450d and 40d - this significantly better as a walk about lens than the kit 18-55 lens.
Image stabalisation excellent - useful in all sorts of situations. Notably soft then wide open on wide angle but OK if stopped down to at least 7.1 - not nearly such an issue on the tele end. Seems very bulky - must be all the extra electronics. The lens tends to block the built in flash on my 400D for shots under 5m.
I bought this lens as part of a kit with my Canon 30D, the image stabilisation is amazing I can shoot handheld at 1/30 second with no blur, great for low light when you don't want to use flash.
The most important thing for me is Image sharpness considering the price it's good but not amazing, some vignetting is visible at 17mm but this can easily be rectified in image editing software and sometimes adds to an image.
I'd recommend fitting the best quality skylight or UV filter you can afford to the lens to protect the front element from damage.
This lens is all you need,a good upgrade from the 18-55 kit lens,give it a good work out on my 400D all was perfect from the 17mm out to the 85mm,much better ballanced than the 28-135 lens when fitted to the body.
Product review or not, I can't help mentioning that the whole purchasing experience was brilliant - the product presentation, the bid, the PayPal process, the seller communication, the product packaging and shipping AND the quality of the product itself which has proved to be completely on specification. I need no prompting to say that I am a well satisfied customer.