Upload & Sell: Off
If your looking to buy the BEST lens for your CURRENT camera in a "normal" zoom type range, then you're looking for the EF-s 17-55 f/2.8 IS. Before you try to give me the gobble-d-goop about the inability to upgrade to FF with that lens, let me give you my thoughts on that. Horse puckey !!!!
You'll be able to recoup 90%-105% when/if you decide to go FF. I've used a host of FF, 1.3X and 1.6X cameras, and 1he 17-55 IS justifies keeping a EF-s mount camera and vice-versa. Don't look at your future upgrade as a hindrance to not buy what's useful RIGHT NOW. I own one and use it all the time on my 7D, I also have a 1DII, and have relegated it to longer lenses and primes/tele use.