There are just so many to choose from, right??? Um. Try Fire Emblem? I'm not that good with games.

I recommend Lufia - The Ruins of Lore for the GBA if you want turn based battle. It's pretty sweet.

Another good RPG is Tales of Phantasia, also for the GBA. It isn't turn based though. Those are the best RPGs in the RGR in my opinion, with exception of Zelda games and DragonStomper for Atari 2600, since I'm not sure that it works.

I'm a mega RPG fan.  So I'll give you a good list.

Star Ocean (SNES) Is a good full long RPG.  You should check it out if you are an RPG fan.

Luna (GBA) Is another version of Lunar for PS1.

Shin Megami Tensei 1 and 2 for SNES are great legendary RPGs and are both translated in the RGR.  For playing the first one look for the one with the english translation with a bug fix.  The first english translation had a bug and it's still in the RGR.

Wonder Project J (SNES) is a fun cherry game where you raise a robot named Pinno to be more human.  You have to teach him how to be a human while also making sure he stays happy, healthy, and loyal to you.

Wonder Project J2 (N64) is the sequel to Wonder Project J.  Same mechanics but you get to do a lot more and it's easier to earn money than the first one.  Only down side is unlike the first game you can not stop the main character Jossette from eating items... 

Hope these will do you well!  I know I had fun with them!

Shining in the darkness is really good RPG,  and Super Mario RPG - The Legend of the Seven Stars.

If you're looking for a humorous, fun RPG, you can't go wrong with Earthbound for the SNES. also, paper Mario for N64 is a really great game. And any final fantasy game is probably awesome.

There are a LOT of really great RPGs out there that you could play, but a lot of it depends on that kind(s) of game that you enjoy.

All three of the Mario RPGs are pretty good (The regular one, and the two paper Mario games.) 

Any of the Dragon Warrior series is worth playing, as are all of the Final Fantasy games in the main series.

Chrono Trigger was one of my staples growing up, and if you enjoy anything having to do with time travel, I'd highly recommend it.

I saw Tales of Phantasia recommended earlier in this thread, its a fun one, and for that matter, ANY of the games in the "Tales" series are worth playing.

The Lufia games were pretty good, I was particularly fond of Lufia 2.

Azure Dreams is so-so as an RPG, but the character development and the relationships that your character is able to build makes it a very enjoyable game.