In broad terms, the ideal commuter for the journey you do/would like to do. Oh, and how it compares to what you ride now.
Titanium framed road bike. Not heavy. Full guard and pannier mounts. Disc mounts. Dynamo lights.
Currently riding alu road bike, which is a bit heavy and very dead feeling. Commute is 17 miles each way now, soon to change to 25 each way with hills.