I drink coffee all day and it is to the point now that it has no effect, not even Starbucks. I would love to hear from anyone that has a coffee brand that gets the buzz up.
'Best' and 'Most Caffeinated' are two different beasts. And even 'Best' is really subjective to the drinker, and even the time of day.
Most of the time, I drink 8 O'Clock Coffee, because I'm just trying to shake off sleep and get going, and it's not expensive for that purpose. When I want to enjoy the coffee, I'll grind up some Kenya AA when I'm in the mood for something hearty, or some lighter Sumatra for lighter cups.
I've been drinking "Nebraska Blend' from GoodSips for the last week, it's a blend of Guatemalan and Columbian coffees.