I guess many of us were waiting for this: the possibility to use Sigma's excellent…
Sigma 18-35mm f/1.8 and Sigma 24-105mm f/4 OS In Stock and Ready To Ship
B&H Photo has both the Sigma 18-35mm f/1.8 DC HSM and the Sigma 24-105mm f/4 DG OS HSM lenses in stock right now (limited supply) and ready to ship.