I would recommend a hybrid: it's lighter than a commuter and it's an upright. It'll handle the varieties of road that a commute can produce, can take racks/panniers/lights etc for commuting but still ride lighter and faster than a "comfort" bike.
and of course since I'm a Trek-head I would always recommend Trek!
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"