I'm glad you don't mind having two lenses instead of one. Someday you may own more than a dozen lenses (I certainly intend to).


My standard advice is to only focus on the next lens you're going to buy. If I had the 350D and the 18-55, I'd probably be looking at the 24-105 also, or perhaps the 17-55/2.8IS. Once you make that purchase decision, you'll need to consider if you want a telephoto next or a true wide-angle lens. Once you get to that point, ask here again and we'll guide you there.


I will say that the 28-300 and the 100-400 are the two white lenses I never plan to purchase.