Decaffeinted tea tends to be fairly mediocre. PaulV says the best he’s found in the grocery store is the Typhoo brand. Also, Republic of Tea makes a pretty good decaf Earl Grey.
Upton Tea has a nice piece on caffeinated tea, and at the end are instructions for decaffeinating your favorite tea in your very own home. Their process gets rid of only 80% of the caffeine, but retains more of the flavor.
Best decaf tea, either online or in a store?