Barq's in a bottle (not a can or fountain drink) Frostop Zatarain's root beer mix (if you like a non-carbonated root beer)
1. frostop (by a mile) 2. ibc in a bottle. note: i dont recall ever tasting abita and i cant get it where i live, but i would guess it is awesome.
Frostop for best local root beer in a frosted mug. Barqs by far has the best widely-available bottled root beer. But some small bottlers are making very good root beer these days.
I pretty much like them all except Fanta, which tastes like some sort of radioactive industrial waste byproduct. I haven't had a Frostop root beer in probably 35 years, but am so glad to know they are still around. My favorites: 1.) Barq's 2.) Mug And, yes, there are few things on earth as good as a root beer float.