In my opinion the Final Fantasy series is definatly one of the best.Call me immature but I also really like the Kingdom Hearts series.It may be judging to the fact i'm only 13 but whatever.
^The poster above me clearly is VERY mature. "LOLZ!" Anyway i don't think age matters when it comes to RPG's.I first played an RPG when I was about 7 or 8. I think it was Final fantasy 7.I managed to get all the way to the Northern crater in disc 3.I still remember quite a lot of the storyline to this day, about 5 or 6 years on.
Well I played Runescape a couple of times but it just never pulled me in.You had to shell out tons of money just to be able to do certain quests and buy certain things. I just found it really boring.