It depends on what kind of RPG you like. DS has a lot of RPGs.
If you're looking for a console I recommend X360. It has Lost Odyssey (I great JRPG that reminds me of the old FF, even the music is composed by Nobuo Uematsu) and Mass Effect. The PS3 also has some awesome RPGs, Valkyria Chronicles and Demon's Souls to name a few.
If you're a turn-based RPG whore like me, I recommend buying a DS. It has lots, lots of JRPGs.