1. DSL (Digital Subscriber Line). Brought to you by the phone company.
2. Fiber Optic. By far the fastest (broadest bandwidth), but also the most expensive.
3. Wireless. The only option for people in remote areas, or in developing countries where there is no infrastructure (Telephone lines) already in place. Very convenient when it works. There are many technical problems with reception that need to be worked out. This technology includes many frequencies on the electromagnetic spectrum including the radio spectrum in the USA.
4. Cable Modem. Brought to you by the Cable TV company.