[mst]

Even though you said you wanted to try something else than Tokina, I still think one of the most interesting options on crop sensors is Tokina's 10-17mm Fisheye zoom.

A note, though: unless you plan to shoot panos, a fisheye lens is a special effect lens, which can be fun to use, but is no real substitute for a "normal" (=corrected) wide angle lens.

-- Markus