Upload & Sell: Off
Many of you ask why did I not include the 17-55 EF-S 2.8 in my list? The answer - a combination of L-bias and future proofing.
If you buy one used you can sell it later for about the same price. It's like a free rental! I paid 33% less than the going retail rate when I bought my 17-55mm, and it was in mint condition. If I keep it that way I can sell it for the same amount if I switch to full frame.
L lenses are great, but if none exist that have a similar focal length range as 17-55, then they're not as effective. The 16-35 hits the wide end, but it's not very long, and the 24-70 (or 105) are not quite wide enough for my tastes in APS-C. The 17-55 is truly a great lens. Right up there in quality with a lot of L glass.
Having a good range for a walk-about lens is really important. If that 15-85mm EF-S lens was a fixed f/4 I'd buy it in a heartbeat! But at 3.5-5.6 it's a little slow on the long end. I'd give up one stop to have more range, but I can't give up two. The fixed f/2.8 on the 17-55 is just too good.