I'm looking for a wide angle lens to be used on my 350D/Digital Rebel XT and (soon) 400D/DR XTi. I don't have very much money at the moment since I just bought a 24" iMac and I'm going to buy the 400D soon as well, but somewhere around $600-900 maybe. The lenses I'm currently looking at are: (Prices are based on the Swedish market - converted to USD) Canon EF 17-40/4L USM ($1070) Canon EF 20/2,8 USM ($680) Sigma EX 20-40/2,8 DG ($580) Sigma EX 20/1,8 DG ($560) Tokina AF 19-35/3,5-4,5 ($285) Right now I would say that it's mostly between the 2 Sigma lenses, but then again I do not want to spend money on something that I feel isn't good enough in a year or so. These photos will be printed up to sizes of 30x40 inches. Is the image quality better in the 17-40/4L or is the extra $500 just wasted? (I obviously understand that it's an L-series lens and that it's top quality, but would you honestly say it's worth the extra cash?) As of right now the only wide angle lens I own is the 18-55mm kit lens, so anything will be an upgrade.