Originally Posted by GarryF
The kit lense with the 40D is 17-85, that's quite a good range and costs about £832
You don't have much left in the budget after that, if you like fast lenses maybe a prime would be an option?
Remember that lenses will outlast several camera bodies so at your budget I think your money would go further if you went for the 400D/450D and spent more on lenses?
For low light is that indoor or outdoor? if indoor consider looking at a t 430EX, this can really help pics indoor with bounce flash
The trouble with these kit lenses is that they often are not very 'fast', ie. their maximum aperture is not very big. That lens has a max apeture of F4, which is pretty bad. With a lens like that, it'll be hard to get a narrow depth-of-field, so for example you wil struggle to take a photo of someone and have the background blurred. Also, if shooting in low light (eg indoors) you will have to use a slow shutter speed which means you can forget taking photos of anything that moves. Yes, you can increase your ISO setting, but then you'll get picture noise.
Digital lenses with decent maximum apertures can be pretty pricey, often pricey enough in fact to deter all but the most serious, or wealthy, amateur.
It's one of the many problems with digital SLRs - the lenses, if you want good ones, will kill you on cost. Of course, you can still take good photos with these kit lenses, you just have to be aware of the drawbacks.