I have a winter bike (alum frame, clip-on fenders) and a carbon summer bike. I started commuting to my current job in Oct so I've been using the winter bike. Once it dries out a little I'll switch to the carbon bike. Other than lights I don't have anything on my bikes specific to commuting. I carry clothes and anything else I need in a backpack. I might add a cross bike with proper fenders and disc brakes for next season.