If you have no financial obligations to protect after 20 years, term insurance might be perfect. Obligations over 20 years require other more permanent plans such as universal life insurance.
Many clients require a mix of term and permanent insurance.
The best policy to buy is the one you can afford, both now and in the years to come. There are too many variables to give a simple answer. This is the hardest part of the process. You need to talk to a good advisor, one who will have your interests at heart. Telephone and Dot-Com agencies are designed to bulk sell insurance.