I currently own the 18-55mm lens (which I hardly ever use) that came with my Canon, and a Tamron 18-250mm f/3.5-6.3. My question is: if I want to be shooting landscape, should I purchase a wide-angle lens, or does the 18mm of my zoom suffice? What are the benefits of buying a new lens unless I wanted to go super-wide with 12mm or something like that? Also, I'm struggling to come up with any occasion that I'll need to use my kit lens ever again. Aside from the IS, it is inferior in every way to the Tamron, so should I now view it as redundant? Your thoughts are most welcome.