Tokina 11-16 2.8 all the way! My hubby has heard great reviews about it. In addition you may want to look at the Sigma 10-20 Wide Angle lens. I know a lot of people who have it and it produces some great images. Be wary though if you are planning on upgrading you 40D eventually. Many of these lenses won't work on a full frame camera (ie...5d or 5D Mark II). I know you probably won't do this in the real near future but be careful or you may have to sell it eventually anyway.