When choosing a bike you need to decide what type of cycling you will be doing. There are three main styles of bikes:
Mountain bikes
These come in many shapes and sizes, the most suitable types for city riding are cross-country or all terrain bikes (ATB). These both have tough frames, excellent brakes, lots of gears, knobbly tyres, suspension forks and sometimes rear suspension.
Both these designs are easy to control and will work well in the city, although it is recommended to swap the knobbly tyres for 'slicks', which are smooth-tread tyres that offer lower rolling resistance on road.
Road bikes
These are designed for speed. They are light, have larger diameter wheels with smooth tyres, good brakes, many gears, and usually drop handlebars.
Hybrid bikes
These are a mix of the best elements of road and mountain bikes, and therefore very well suited to urban cyclists and leisure riders. They have larger diameter wheels, like road bikes, but slightly wider rims and tyres, making them stronger. They maintain good speed on the road and give the rider good control and stability. Like mountain bikes, they come equipped with lots of gears and excellent brakes.
There are several other types of bikes available including tandems, recumbents and tricycles. For more detailed information, visit the links provided on the right hand side.
Further Information
The best place to find out which bike is best for you is to visit a local bike shop. They can give you advice on the correct size and let you try out different types of bikes.