Here is one of my commuter bikes. I bought it in August 2008, but this 1994 still had the original store price tags on it, the nubbies on the tires, everything. It is a Nishiki Sport XRS hybrid. In the 90s, "hybrid" meant a bike that is a bit of a cross between a road bike with a rigid diamond frame, and a mountain bike with flat handlebars and an upright seating position. The wheels are narrower than a mountain bike's, but wider than a road bike's, and the tires are also somewhere in between in terms of tread pattern. Some people still talk about hybrids, but the use of the term has dropped off some.
When I got it, it looked like this:
By adding a rack, a trunk bag and a water bottle, I had a basic commuter.
I also think you need lights and a bell.
Eventually I decided the trunk bag was just a little to small to hold what I carry to work, so I got panniers that hang off the rack.
Now, why is this a good bike for commuting?
. It has an upright seating position that lets me see traffic clearly (and also be seen)
. It has eyelets to mount the rack (not all bikes do)
. It is sturdy but lightweight
. It has hybrid wheels and tires that are relatively speedy but handle well on uneven city streets
. It has fenders to keep from getting wet when going through puddles
. It has toe clips
I haven't mentioned toe clips previously. Bicycle purists will say that the best pedals are "clipless pedals" where there is just a very small pedal that clips into a cleat on a specialized cycling shoe. Beginners are used to platform pedals (traditional pedals). For commuting, I like to go for the middle ground- toe clips. With toe clips it is easy to get your foot in and out of the pedals (easier than clipless pedals), but they are more secure than plain platform pedals and give you more efficient pedaling. They are a compromise between platforms and clipless that I prefer when I'm out in traffic.