man this is kinda hard so im going to bend the rules a bit and list my favorite rpg on specific console's
every generation i roll with playstation AND nintendo
right beside my n64 was a ps1. right beside my ps2 was a gamecube and right beside the ps3 is a wii so yea :)
SNES: i went back and played Chrono Trigger, Earthbound and Mario RPG and i LOVED them but have not beat any of them yet
N64: Paper Mario
PS1: FF7 (followed by ff9 then probably legend of dragoon)
Gamecube: Tales Of Symphonia(followed very closely by Paper Mario 2)
PS2: im sorry but i still to this day cant decide my favorite rpg on ps2 but it's out of Final Fantasy 10, Kingdom Hearts and Dark Cloud 2 (have not played Dragon Quest or Persona and i did not like Tales Of The Abyss)
Edit: i almost forgot about gameboy
GB: Mario And Luigi SuperStar Saga
^^ this is really the only game i mainly buy gameboys for(even though i did not enjoy partners in time and bowsers inside story as much as the 1st)