If you have your own home, a whole house device through which all incoming lines - power, cable, satellite, phone, etc. - pass through is the most prudent approach by providing protection to all devices in your home. The choice of such an approach is a personal matter and requires a subjective assessment of the risks. If you happen to live in an area with known lighntning activity - Florida, parts of the Midwest, etc. - this is a very sensible approach. It can be installed by an electrician, yourself (provided you're comfortable around electricity) or even rented from your local utility company.
If that's not your cup of tea, then buy any one of the point of use devices making sure it also has provisions for incoming cable should do the trick. Guide yourself by selecting units with the highest joule ratings and consider any other features that many be desireable.
"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House