what the others before me said.
If we're talking about final fantasy my favourite will of course be FFVI, followed by... FFIX maybe?
How come nobody mentioned Chrono Trigger?
I also like the Persona series a bit but I think the Shin Megami Tensei main series is actually better. My favourite is Shin Megami Tensei: Nocturne... and after that... Persona 3 I guess... didn't like Persona 4 a lot. Really looking forward to Persona 5.
You might also want to try the Lunar series (Silver Star and Eternal blue). And wait...
the Suikoden series? My favourite are Suikoden 2, 3 and 4 XD 5 was kind of boring... XD
Ah! why not try some game from the Dragon Quest series?
There are so many...
- Shadow hearts
- Star Ocean: the second story
- Earthbound, Xenogears (which other people already mentioned)
- Breath of fire (3 is my favourite one)
- Legend of Dragoon (oh Lavitz... :'( ...)
- and the list goes on and on...
As of now... these are all I can remember...
PS: forgot to mention Final Fantasy Tactics, if you like these games. Along with Tactics Ogre.
PS2: I wouldn't call Mabinogi a JRPG simply because it's a Korean MMORPG actually XD