If you have a DS, I could give you several suggestions. My strongest one, however, would be Shiren the Wanderer. That's the game that really shifted my mindset towards RPGs in general.

Might sound a little abstract, but the key to getting 'good' at Shiren is not levelling up your player character, but levelling up *yourself* as the human player. If you can get over the 'start back at 1 when you die' thing, you're set for something pretty special.

Shin Megami Tensei games also get my vote. The World Ends With You on DS also has my 2nd favourite RPG combat system, behind the 360's Tales of Vesperia.

Branching out just a liiiiiitle bit more from the standard definition of 'RPG', Yakuza and Yakuza 2.