Two of the best coffees have been ignored in this discussion. Free and Hot.

The best cup of airport coffee is the extra cup that the Capt shows up with after making a trip to Starbucks, Dunkin Donuts, Seattles Best, Carribou, etc...

As far as airplane coffee goes. I thought the only options were hot/bitter and cold/bitter. Until a senior FA poured bottled water into the coffee pot, left it on the hot plate for an hour and poured it by hand through the filter into another pot. Best airplane coffee ever. Some of the ladies really do care.