Wide-angle for DX is a problematic area, and is not likely to improve, as far as I can see. The fact is that as DX is the natural home of the mainly long-lens user, FX is the natural home of the mainly wide-angle user. There are relatively small gains from the smaller format in the wide-angle range because when the mount size and the flange focal distance are the same lens complexity scales with actual focal length. So the DX 12-24 f/4 is $1100 and the DX 10-24 f/3.5-4.5 is $900, while the FX 18-35 f/3.5-4.5 is $750 and the FX 20mm f/1.8 is $800.
The Nikon 10-24 and 12-24 zooms are good but not great, relatively bulky, and expensive new (although the 12-24 is a bargain used - which tells you how many people bought it and then sold it). There is not much to choose between the 10-24 and the 12-24 (other than the extra 2mm).
The Tokina 12-28 is cheaper, about the same size, and also good but not great. The Tokina 11-16 f/2.8 and the newer 11-20/2.8 are also good. Tokina build quality is excellent - the Tokinas are the clear value for money choice.
If 24mm equivalent is wide enough the Nikon 16-80 is a good 16/2.8.
My two cents worth is that the choice among the zooms depends on how you photograph. If you like 35mm as a walk-around focal length the 12-24 can be a one lens kit - I often use it that way in cities (the Tokina 12-28 gives you even more flexibility). If you are carrying the 16-80 the Tokina 11-16 or 11-20 would be the obvious complement.
I have no experience with the third party primes, except for a brief test of the Zeiss 15mm f/2.8, which seemed to be excellent but is outside my budget.
