Abita(In Abita Springs Louisiana) has the best tour ive ever been on. 2 hours of unlimited beer...only allow 20 people on each tour. Stone is beautiful. Im personally a big fan of the really tiny little ones where you can talk to the master brewer for hours. Went to one in San Diego called Hess brewing. Great beer brewed out of what looked like a public storage unit.
Stiegl brewery in Salzburg Austria. There is a museum that has the history of the brewery and technologies used over time. You also get to sample all the beer with entrance fee. This is what got me interested in homebrewing.