I like games where I can play of role of my own defining (within the confines of the game itself, mind) without having to worry to much about stat juggling, equipment selection, party make-up and the sort.
That noted, I don't feel JRPGs are actually such in terms in the RP since I'm not playing a role. I'm simply taking the predefined character and leading him/her to the next plot point, battle, or cut-scene.
Observation: I realize I didn't really answer the question. I guess I'd say the Mass Effect series since it's the closest I've come to recreating any one of my characters in a game (next to Saints Row/2, but that doesn't really count as RPG).