My best memories of FFXI were the expansions. Doing sky for the first time, beating CoP and ToAU, running around in Sea. Other than that, I had a lot of fun playing Blue Mage, going out into the middle of nowhere to try to solo learn skills (needing a party to learn the later ones was just horrendous design though).
The only other similar game I have played is the original Guild wars, but I don't remember much of it, it was more like a Co-op RPG than an MMO.
