My commuter is a Kona Dew. (I also rode it in a triathlon)

I know another TE'er rides a Kona Smoke as her commuter.

both are under $400, and as my LBS says, "they are bombproof"

www.konaworld.com/bikes/2k7/DEW/index.html

www.konaworld.com/bikes/2k7/SMOKE/index.html