My two cents worth. Be sure you get a bike that can take fenders and a rack for your stuff. You don't want to look like a skunk on rainy days and you should let the bike carry your work clothes etc. Before you choose, take the candidates for a decent ride to get a proper feel for each. I'm guessing that the route you intend to ride is the same one as you would drive. Check out some maps, there might be alternate, less busy roads that will get you there with less stress.