Things to think about when buying a new bike

Who will you be riding with?
What do they ride?
What type of riding will you be doing--street or off-road?
How often do you anticipate riding your bike?
What type of bike did you have before or currently own?
How much money are you willing to spend?

The first three questions go hand-in-hand. If you are riding with someone, it would be useful to know what they ride so you can get something similar. Road bikes get higher speeds than mountain, hybrids, or cruisers but they can't go on dirt. Mountain bikes are versatile but they tend to be heavy and slower than road or hybrid bikes.

Hybrids or cross bikes are made for the road and have upright handlebars, as opposed to road bikes which have drop bars. Hybrids are also less expensive than road bikes and offer more comfortable riding. Hybrids can accommodate fenders and/or racks. These bikes start out at around $300.

Comfort bikes are exactly what they are, made for comfort. They are less efficient but comfortable. These bikes will start out at around $250.

Road bikes are fast and have a dropped riding position. Road bikes are made for speed and are lighter than any other type of bike. Some road bikes can handle racks and fenders. Road bikes are going to start at around $750.

Mountain bikes are slower on pavement but they have softer rider and can go on almost any surface. Most mountain bikes have a front shock which helps cushion the ride. These bikes start out at around $300.

Looking for more information? Check out these articles:
Got a New Bike?
Where do I go from here?