I would kill a baby bear for that Sigma 70-200. A baby bear.
Im shooting with a Tamron 17-50 2.8 and i wish i chose the sigma equivalent after using my friends... just a better build and feels more quality, not to mention performance. Also it comes with like a ten year warranty im pretty sure?
Sicks shots though, pretty much all of them were stunning. Thats a good thing to see to because people clog there flickr's with shit sometimes..