I love em both, but for the sake of the argument, I'll choose Folsom Prison. San Quentin has some of my (and most people's) favorite Cash tunes, but Folsom just has more obscure songs that I really enjoy. Especially, I Got Stripes, Cocaine Blues, Orange Blossom Special (not that this song is obscure though) and Dirty Old Egg Suckin' Dog! So unfair to have to choose!
"If it were beneficial, their father would produce children already circumcised from their mother. Rather, the true circumcision in spirit has become profitable in every respect." -Jesus, from the Gospel Of Thomas