Two backbone configurations could be Cable Modems and a FIOS.

It is used for transmission or receipt over cable television lines, and is is used primarily for connecting to the Internet. A cable modem converts analog data signals to digital form and vice versa to transmit signals over cable lines much faster, and it is not to be confused with a telephone modem. Transmission rates average around 1.5 mbit/s. Because cable is shared among multiple tenants, connection is usually slower during the hours most users are on the internet. Faster transmission is actually possible, but in addition to shared overload, speed can usually be restricted by the cable company’s connection to the Internet. Cable Internet access is competitive with DSL. * PROS: Fast for the value * CONS: Initial cost and limitations of available locations.
FiOS
FiOS stands for Fiber Optic Service that connects to the Internet using light over an optical network. In your home, you still connect your computer through copper wiring. The advantage of FiOS is that it can provide higher speeds than traditional copper wire connections such as DSL or cable. Some Internet providers offer multiple options, depending on the area you are in. More populated areas are more likely to have FiOS available. Check with your phone company or Internet provider for more information. * PROS: operates at speed of light * CONS: limited to one provider (Verizon) and not available in all areas
Of course, a lot depends on your actual Internet Service Provider. Here is a good resource to dig through when choosing the Internet Access type for your business: * ISPcompared.com gives you the edge when it comes to comparing Internet service providers. We assist you by providing useful tools, user reviews, and user submitted ratings. ISPcompared.com helps make finding a faster more affordable ISP quick, easy, and painless. * Top 10 ISP providers’ reviewes by Top Ten REVIEWS, who are dedicated to giving you the information you need to make a smart purchase.
According to me first cable modems are less expensive monthly fees, but are slower than FIOS.

A company can get away with putting a cable modem and router or FIOS and a router at each office locations with a Static IP and network all of their site to site servers that way.

Alternatively they can go with a leased line solution such as Frame Relay, or a DS3. These options are typically more expensive than cable modems or FIOS and can match the same speed as FIOS; however, they do give the option of management and network planning from a central location to the company, where FIOS or Cable Modems made management and configuration much more difficult.