Phantasy Star Online on Dreamcast. I still play to this day on private servers.

Guild Wars 2

World of Warcraft is the only MMO I played. Loved it, played it for like 5years intensively, then I realised that I should move on cause it was consuming to much of my time.

The first mmorpg I played was FFXI. 2003-2011

I wish I can get that 8 years back lol.. Now I have interest in FFXIV lol

WoW, The amount of time I have spent on this game is insane. I am a type of person that really does not like doing the same thing over and over. For example I dislike watching movies twice, reading books twice, beating games twice. But to me WoW never seems to get old.

Does League of Legends count?

(This is more of a question because that's the only more than 5 people multiplayer I've played.)

Only play 1v1 starcraft.

For me Cabal and Rohan are the best f2p MMORPG.

World of Tanks :)

vanilla Guild Wars

WoW

World of Warcraft is the only MMO I've ever played, so that, really. During my time playing it I had no desire to try out anything else, aside from a brief period when I lost a bit of faith after Wrath of the Lich King launched (but I still stayed with the game for a further two expansions, so it didn't last :P)

I've played Phantasy Star Online but I'm not entirely sure it was an "MMO" RPG. I've also played MAG which apparently is listed as an MMOFPS on Wikipedia, but again I would consider it lacking the "MMO" aspect.

Kind of off topic, but in future I'm planning on trying Final Fantasy XIV (when it comes to PS3); and Planetside 2 either if it comes to PS4, or when I decide to upgrade my computer.