I have been for many years a landscape painter both in the Southwest and on the Northeast coast. I used a Elan II to gather reference material. I find myself turning my creative drive toward photography and have purchased a Rebel XTi. The basic lens I have is the kit lens from the ElanII-an EF 28mm-80mm. I want to continue to work with land and seascapes as before but with the camera and PS. My question is which should I invest in the 17-40L or the 10-20EF? My thinking is, the 17-40 would be on the camera 90% of the time however I am limited to 27mm for the widest and would need to stitch for anything more. The 10-20 gives me what I will need on the wide angle end but is less versatile. Is my EF 28-80 good enough for making moderately large prints thus pushing me toward the 10 to 20? (I have adequate telephoto coverage)
Please give me some thoughts and opinions on the subject; this is a new world to me.