Renting and looking at the imaging links are terrific ideas. You'll find that you'll like wides the more you use them, the really wides are likely too wide (once the new wears off), but something more than 18mm (assuming that you're DX) is really nice.
My Nikon 10-24mm is acting up and is going to the shop this week. It must of got bumped, but in the 12-15mm range it was very nice. A lot of folks rage about the Tokina 11-17mm.
The theory is that you can hand hold a wide lens at a slower speed than a normal or telephoto. Good photography always favors rigid camera technique.
A lot depends also on what you enjoy shooting and your personal goals.