Definitely Invincible from FFIII. It has a free "inn," a full repertoire of shops, a Fat Chocobo for item storage, and a cannon that fires on all enemies at the beginning of every random encounter. And beyond the practical assets, it has a unique aesthetic appeal: up to this point in the series, airships had always been nothing more than flying boats (or flying submarines, in the case of the Nautilus), but the Invincible looks like a flying city. It doesn't even land; when the characters exit, they just take a ladder down to the ground, leaving it to hover constantly like the badass it is.