One of the new Sigma lenses just announced is a 10-20mm f/3.5 EX DC HSM. The old version is f/4-5.6 variable aperture, with no HSM. That should be a really excellent improvement. I wonder if the auto/manual focus clutch will work as well as Tokina lenses now? Either way, I bet they sell a ton of these.
I was lent a Sigma 10-20mm recently and it did have HSM as it worked on my Nikon d40, was thinking of buying that as my next lens but then i saw that the tokina 11-16mm has good reviews as well, but sadly it won’t focus on my camera. Maybe this will be a good option.