can't go wrong with the Jamis Coda Sport at all. it's what I've been commuting almost daily and doing various errands and longer fun rides on for about a year and a half and it's a great flat-bar road bike.

with DC-area pavement being the way it is, you'll probably want to replace the stock rear wheel with a tougher touring or cyclocross rim and 36h hub/spoke count, and possibly swap the 28c tires out for 32c tires if the pavement is REALLY bad where you are (and since you're riding on the bike paths here that's probably the case), but other than that, it's the perfect flat-bar commuter. just the right combination of speed, good components, and durability.

which shop was the Jamis dealer?