We get Folger's for quotidian use (economical), but I prefer Gevalia or Jacobs. Cafe Bustelo is also good, for a more robust cup. I also like Eight O'Clock and Seattle's Best. We always got Eight O'Clock from A&P when I was growing up.
Postum is also good for those times when caffeine just won't do. Post discontinued it several years back, but a small company (if I had to guess, they're probably Adventist-connected) in Charlotte NC started producing it again. It is just a little "off" from what Postum was when Post made it, but close enough. You do have to put it into a mug of cold water, dissolve it, then heat it in the microwave (or whatever you heat it in) --- when you stir it into hot water, it makes clumps of brown goo. Design flaw, but at least you end up with basic Postum, which is more than you'd have if someone hadn't started making it again.