I am pleased with my Canon 400d and currently use my older lenses. One result is that the digital makes the lenses more powerful by a factor of 1.5.  Which is great for my  75 to 300 zoom but means I have lost the wider angle on my 28 to 90 zoom. Am i correct in thinking that  17 to 40 is the equivalent ? 
This would be a good chance to get a specific wide angle zoom  but I am not sure what would fit besides Canon lenses,
thanks confused of Scotland !