[Garyh]

Originally Posted by John K

The Sigma 17-70DC Macro is very good as well if your budget is in the $400-$500 range.

See some shots here mainly with a 400D:

http://www.flickr.com/photos/johnkaz...7594361091590/

I agree with John, if you are on a budjet you can`t go wrong with the sigma 17-70 dc lense.Has some great reviews and it will be close in optical quality to the canon 17-40 f/4 ..yet half the price. Its a little soft at 17mm but from say 24mm + its excellent..
The standard lense you mention, 50mm f/1.8 would also be a good choice but if you can afford it go for the 50mm f/1.4...much better corrected lense..
Cheers...