Your best bet would be to go to a local bike shop. For cruising around town mainly on the road try a comfort bike. Comfy seat, lots of gears for the hills and not very expensive. Avoid stores like walmart or target, bikes sold by these stores are low...
A fitness bike is more tuned to exercising your muscles by positioning your body in a certain way to maximize calorie burning. An urban bike has more comfort features for heavy use (especially if you live in the city, and use your bike frequently)......
There are 3 common types of bicycles right now... road, atb, and mountain. A mountain bike is built for off road use in rough terrain, and usually has suspension for better handling. Suspension is NOT for comfort, but is to keep the wheels on the gro...