I can recommend a Sigma 15-30 f/3.5-4.5 lens - it's quite wide on a 1.6 crop body. The optical quality is nice, the lens is big, but surprisingly not that heavy, very good build quality. You can get it for $479 here
(for some reason it's about $100 more expensive in B&H ...).
You can see a few samples from this lens here
and here
.


