Yup, its a necessity if you have a family. You need to be able to replace your income if you are gone.
I would stay away from Primerica, since it is a pyramid scheme. You are unlikely to be helped by a knowledgeable agent but rather sold a premium committment by a guy trying to make some part time cash who won't be around to answer your questions in the future. Most primerica "agents" are out of the business within 6 months.
Term is obviously the least expensive route to go and realistically, is all that is affordable to most people when trying to properly cover a need. All of the A+ rated companies will have conversion priveleges that allow you to convert chunks of your term coverage to permanent (whole life, variable life,etc.) coverage if you should find the desire (and the $$) to do so.
Don't be afraid to shop around and educate yourself about what is available.