Just thought I should mention it, as with a quick search it was only mentioned once in the forum, and not in Other Games. Vanguard: Saga of Heroes is a fairly impressive MMO. You can go the usual combat way, fighting everything, and all that. But you never have to be great at combat to have fun. There's plenty of crafting, and if I remember correctly, every item in the game can be crafted. The crafting process is actually pretty nice too; you get a set certain number of points, which are mostly spent doing necessary tasks, such as sawing the wood, piecing things together, but you could also polish the item, sand it (when dealing with wood at least), and thus increase its quality, from F to A. And of course, when you first start out, getting above a D is near impossible, as all the necessary tasks used up all of your time, hehe. There's also crafting that deals with larger constructions, where you can build your own homes. I think you can even make villages or cities, probably only if you join a guild though, but I won't delve into that, as I'm not sure. You can even make ships.
There's also a Diplomacy way, where you can, well, self-explanatory. Talk with others to incite them for war, persuade, or just get on their nerves, with logic or otherwise. The whole diplomacy thing is played in a card-game, where a card that you play is the communication technique you use. It's been a while since I played, so I can't remember too much about how the card game works.
But yeah. Very large world, so large that characters can go into "Caravan Mode," where they automatically go offline and can't come back online for 8 hours or something, but in the meantime their characters follow the party leader, so that only he/she has to make a great trek across the land. Once again, long time since I've played, and I never used it, so not sure how great it is.
The biggest problem(s) I had with it were the character's faces, which look like old dolls, and that it costs twenty dollars USD to play per month, which is more than most MMO's that I've heard of. In fact, if it weren't for such a high monthly subscription I'd probably still be playing it.
On the topic of what makes an MMORPG fun, to me personally, exploring. There is nothing I enjoy more in a game than going into an area I've never visited before, or better yet never heard of before, or even better yet, an area that nobody else has ever seen before. In Vanguard, at least when I played (a week or two after it came out) new places were discovered often, so there were always new things to be seen, as it was a new MMO. I'm guessing by today pretty much every place has been found though. But yeah, exploration and discovery.