Believe it or not, Dunkin Donuts isn’t bad. However...
If you want a GREAT cup of coffee check out Terroir. I think it is
www.Terroircoffee.com
The company is owned by George Howell. He started Coffee Connection and now has the most phenomenal coffee beans. They are not cheap but if you are a coffee addict they are the best. I get their fairly ‘low end’ Costa Rican La Minita peabeans.
It is really important to have a burr grinder and really good water with no chlorine. Also important - non-chlorine filters. The brown ones taste like paper bags (do a taste test, you’ll see) but the non-chlorine ones are good. I get them from Green Mountain Coffee. They used to have good coffee but their customer service was poor. Their coffee filters are good though.
If you like coffee but don’t want to spend a lot of money, at the very least get a burr grinder. It makes all the difference in the world.
I highly prefer the metal filters vs the paper ones. Paper absorbs the flavor and also breaks down, so you have little pieces of paper in your coffee.