It was the original Neverwinter Nights until I played one of the modern Bethesda FPRPGs. Can't remember if it was Fallout 3 or Oblivion but after that I've found the 3rd person style severely lacking in terms of making me feel like I'm actually in the world rather than watching the actions of a little marionette.
So I'd say a 3 way toss up (0_o) between Oblivion, Fallout 3, New Vegas. Didn't like the world in Skyrim though.
MMO wise, I'm not very well versed, having only played GW, Neverwinter and a bit of GW2 and Tera. Favourite is Neverwinter so far, they've really got the action combat down and although some people say it's world is rather small for an MMO (it is, from what I can tell) what's there is well made and being more of an RPG player than MMO it suits me fine.
JRPG wise, Secret of Mana is the only one I've ever liked and that was about 20 years ago and my tastes have changed to the point that anything that vaguely JRPG like repulses me pretty rapidly (e.g. Tera, I liked the combat, almost as good as Neverwinter and had a couple of cool mechanics that were better, but aesthetically it really wasn't my cup of tea, unless it was one of those times I accidentally made it with 2 week old rancid milk).