I have a Canon 550D DSLR that I've been using for the past 6 months to learn photogragphy. It has the 18-135mm lens and I also got the 50mm/1.8 lens. As I learn more I now think it's time for me to get more lenses.
I mostly shoot nature and cityscapes. I want a lens that is sharper and faster than the 18 - 135mm and more specialised for the type of photography I like. I was thinking of adding a wide-angle and a telephoto lens to my gear. Any suggestions on which are good Canon (or compatible lenses). I can go as high as $700-$800 (each) but can't really afford the more expensive ones.