I have a 400D and got a 50mm 1.4 and the kit lens. i think is a good camera, not the best, i want a 5D for the full frame capable or maybe a 40D for liveview and more ISO. I think the best option is buy a new lens (maybe a Tokina 11-22 in wide or a T...
In the 17-85mm the good point is the IS. Is hard the choice of the lens, but U must think in the L series =) There is a telephoto 70-200 f4 L (canon). Isn't the best telephoto, but isn't the most expensive.