I'm about to start Final Fantasy XIII-2 but I'm already thinking about the next game I'd like to start for my XBox 360. I really like RPGs and I usually lean toward the JRPG style. I prefer some sort of turn-based, although ATB combat is fine. I'll try to go through the RPGs I have played (so you'll know not to recommend those) and describe what I like and what I didn't:
This game was exactly what I was looking for. Great combat system; fun characters and a good plot.
Dragon Age: Origins
It was... OK, I guess. I was expecting more, somehow. Combat was kind of convoluted and I found it difficult to use abilities/cast spells. Storyline was OK.
Star Ocean: The Last Hope
I also enjoyed this one. Combat was sort of real-time but the plot was fun and the characters grew on you. Liked the achievements system and the side quests.
Final Fantasy XIII
I really enjoyed this mostly for the combat system. Finally I don't have to make the small decisions and can just focus on the paradigm my party is in. I thought that was a brilliant move. Yes, it's linear - I don't mind linear.
Mass Effect Trilogy
This is where I departed from my comfort zone in terms of combat. I nearly gave up on ME1 because the controls sucked so bad, but the story kept me going. ME2 and 3 improved the combat but took away the RPG-ness. As much as I love the universe, and I'm totally on board for ME4, it would take some convincing for me to try another shooter/RPG.
Elder Scrolls IV: Oblivion
I gave up on this one 15 minutes in when I was killed by a sewer rat in the opening dungeon because I couldn't see the thing or swing my weapon at it. The control scheme was completely unusable for me.
Enjoyable for the most part but it really felt more like a Zelda style adventure than an RPG. Combat was ridiculously easy, but... it was way too non-linear for me. I appreciate an open world but it felt like there was too much to do so I didn't want to do any of it.
RPGs for other systems I totally loved
Final Fantasy X & X-2 (PS2)
Legend of Legaia (PS1)
Legaia 2: Duel Saga (PS2)
Pretty much any Wild Arms game
RPGs for other systems I didn't care for
Chrono Cross (PS1)
Final Fantasy XII (PS2)