Well the smaller numbers are the wider angles, and with your crop factor you loose a bit of frame,.. perhaps the tokina 11-16mm? (17.6 - 25.6 with a 1.6 focal multiplier) $530ish US, might be a bit high.. Do you have a budget?
These threads usually see a lot of action so I'm sure some more informed opinions are already on the way.
-Shea