There is also a new Tokina 14-20/2 for DX format (yes f=2) Filter size is 82mm.
Compared to the Nikon 10-24, take your pick: do you need the faster aperture of the Tokina 11-16/2.8 or 14-20/2, or the wider angle of view and larger zoom range of the Nikon? The two Tokinas have rather restricted zoom ranges, could almost be considered "flexible primes" rather than a zoom.
As for the Sigma 18-35, heard mostly excellent things about it, except it is heavy and perhaps AF not accurate on outer AF points. It only covers a medium-wide to standard zoom range, in your original post you seemed to be asking for wide to ultra-wide options.
If you intend to shoot landscapes etc in good light or from a tripod with the lens stopped down for extra DOF, I would go for the Nikon. If you intend to shoot handheld in poor light, the faster alternatives might be better.
