Looking at my sig, you'll see my newest toy I had a friend grab it for me, so I have yet to lay my hands on it, but he tells me it's really, really nice!
You'll also see my lens collection thus far. I was thinking of getting a 17-55mm for my 50D, but fate stepped in and granted me a 1Ds for a steal.
So the question begs... what lens should I get? I find that my 50mm is often too tight on my 50D, but I bet it's gonna be sweet on this thing. I find I most often use my 10-22 at about 18-20mm, so maybe a 17-40?
Edit: Want to spend less than $1000 for a used lens.