Check out the new Jamis 08' Commuter. I have last year's 3.0 model with the Alfine group and love it. I think the new model is the 4.0?
It has 2 rings with a derailer and chain tensioner plus they added disk brakes. Sheldons shop gave the original bike last year great remarks and they stocked it as well. At $539 (for the 3.0) you'll have plenty leftover to add quality accessories and still remain under $1,000 for a nice, simple all weather ride.