My buddy and I were talking about how much fun FFXI was back in its hay-day (summer 2005ish).
I'll never forget the excitement of claiming Argus and getting a peacock charm.
Or having a level 40 as my highest character, random /telling 4 summoners online and going with my paladin friend and getting ourselves Voyager's Sallets before we could even wear them.
If you put the effort in FFXI could give you satisfaction that no other MMO could.