If you deal with bad weather and are hauling loads back and forth a touring bike or a cyclocross bike would work. If you do not plan on hauling loads and have nice dry weather a regular road bike would also work. All in all I would recommend the method I am converting to. One bike for bad weather and hauling loads- my touring bike. Another for dry weather and to go fast- my soon to be more racing oriented road bike.
If you are more comfortable on a flat bar bike, last year I rode my commute 30 miles RT on a hybrid. It would be slower but doable. Or even a flat bar road bike.