In that case, you'll probably do well starting with the more action-oriented RPGs. I would recommend Tales of Symphonia (Gamecube), Fable II (for a Western RPG), or Mario & Luigi Superstar Saga (GBA).
If you want something more traditional, I started with Final Fantasy IV, and can vouch for the DS remake. Chrono Trigger is also one of the best RPGs you'll ever play.