Wow, that's a huge purchase. I'm glad we got another Canon guy on here.
Just a reminder...don't expect to be Ansel Adams because you got a shiny new white lens...lol The guy I bought my 17-40L from was a nice kid that liked to take photographs. He told me he bought the lens because it had a L series designation on it. He told me he expected everything he shot with the lens to magically be National Geographic quality photos. When everything he shot didn't turn out golden, he decided to sell the lens. The moral...be patient with your equipment until you learn its full capability.
I smell a photographic road trip in the near future...
shawn