zonatandem

Rode a road bike for 16 years as a commuter.

reverborama

My commute is kind of weird. It's 26 miles each way, 85% of which is on bike paths or bike lanes. The remaining portion is on a couple of roads with not too much traffic and very broad shoulders. The drive in is quite a bit shorter because I cross the Minnesota river and have to go quite a bit out of the way to get to a pedestrian crossing. I don't have a shower at work. I take my clothes and tomorrow's lunch in to work the day before so I don't have to carry anything with me. I ride a road bike but I have to chant "no chasing, no passing" to myself over and over -- at least on the way to work! I made the mistake the first couple of times of gettng too sweaty and a little tired trying to see how fast I can get to work. Now I force myself to take at least an hour and a half so that I'm not beyond cleaning up with a washcloth. I see lots of commuters with panniers and I wonder if they think I'm just some guy out for a pleasure ride. I watch the weather and only ride on nice days so the most I've ever managed was 3 times in one week. I used to take a route that was 2 miles shorter but it goes right down to the level of the river so there's too much climbing and this one time I ran into a bunch of tiny flies that stuck all over me. It was really disgusting even by my standards. I had to stop at a house and hose myself off with their sprinkler before getting to work. I don't go that way anymore.

HiYoSilver

Agree with most others. There are a few questions which should provide guidance:

1- do I have secure parking at the other end so theft is low risk and I can ride a good road or tri bike?

2- are the roads passable enough for thin tires or just to heavy with glass and deep potholes

3- do I need a bike trailer, or can I carry what I need on my back with an excellent back pack

Beyond that it's all what makes you happy: color, fit, type of bike, etc.

Just keep fun in the process...

billydonn

Get a cyclocross bike. Nearly as fast as your roadie + can equip with 28mm tires (or bigger). Many will take fenders if you want. They come in CF too! Very fun.

Artkansas 

To me, it all depends on the commute. For decades, my commuter was a 10 speed that was solid, dependable and fast. Fine for flat California streets and mild hills. But when I moved to Arkansas and realized that I'd have narrow potholed hilly streets I changed to an old hard tail Specialized Hard Rock. My last commute was 10 miles each way, hills, but one section that was great for cruising, and I pulled out the short wheelbase recumbent.