Which interest bearing account is best for people who won't need access to their money for several months or longer?

The correct answer to this question is a certificate of deposit.

A certificate of deposit is an interest bearing account that pays a higher rate of interest than a savings account or interest bearing checking account because you are committing to leave it in the bank for a specified period of time. The CD could be for serveral months, or extend out to multiple years. Normally the interest rate will increase as the length of time increases.