Rift: By far my favorite of the games. I don't play it, though, because they've basically abandoned even the pretense of enforcing any of their rules. Wanna tell everyone that "abbos" are basically monkeys and ought to be gassed? Talk about how you want to rape someone's kids? Spend your evenings making jokes about how much you hate gays? Go to the designated RP server just to stalk RPers around and harass them? Right now, Rift is your best choice. Particularly mystifying, because in basically every other category, Rift's devs strike me as among the most passionate and skilled in the field, and also some of the most engaged with their customer base. Except on this one thing. Unfortunately, social interaction is the biggest thing by far about MMOs for me. And yes, I'm aware that every game has some of that. What's different is that in Rift, the same person can be using the same character to do this for, quite literally, over a year without them being told to stop. One person I know once got into an argument and told another player he was going to rape them with a knife; he did get contacted by a GM, who apparently suggested that maybe he should tone it down a bit. F2P model is, thus far, surprisingly non-abusive. In particular, if you want to just play the game without ever paying a penny, that's actually viable. Performance not nearly as good as it should be, but they're actively working on it; until recently, the bulk of the game's rendering engine was not multicore-friendly.
FF14 ARR: The parts that are good are amazing. But in other respects, they have taken incompetence to a whole new level. It took them ages to solve the VERY challenging problem that their spam filter wouldn't notice that you were sending 2-3 messages a second to a channel as long as each message varied by a few characters, for instance. Rumor has it that they've had exploits which allowed malicious users to, for instance, sell a stack of 99 cheap items to a vendor, but inform the game that they had sold very expensive items. Or instantly level themselves to the level cap by handing in a single quest. Probably mostly fixed by now, but that these things were wrong in a game which is already a re-release from a company with prior experience is insane. On the other hand, very pretty, very atmospheric, good storytelling. But it is a Final Fantasy game; it is literally a few minutes from when you create your character to the first time you are able to move, and even then you simply aren't allowed turn around and walk the other way until you've talked to your quest giver. No, really. And yet, it's pretty fun. Sub-only. Performance is pretty decent, although the previous release was apparently bad. Special mention for the very deep and full-featured crafting system, which I personally find to be the most fun part of it.
D&D Online: F2P model a little harsher than, say, Rift. However, a sufficiently patient player can probably unlock all the restricted content through in-game activity. Or just sub for a while. This game is not really D&D -- if you are familiar with the 3.5 rules, it will screw you up as much as it helps you. It is, however, the minmaxer paradise. This is a game which absolutely, unconditionally, rewards people who are good at thinking out how to make their numbers stack for best results. Very unusual mechanics in a number of ways; for instance, you don't get XP from killing mobs, only from achieving objectives. No automatic healing just from not being in combat, and if you aren't playing with difficulty turned down (there's settings for that), you can run out of resources trying to do a quest. Graphics are sort of unimpressive compared to a lot of other games. On the other hand, has a native mac client, which can matter if you have a mac or have friends who prefer the mac. Runs well on older hardware. Insane depth of character creation, and after you cap out, you can restart the character as anything else, only with small permanent bonuses. Which stack.
TSW: Buy-to-play. Lots of stuff you might want to spend money on, but mostly that's cosmetics, and you don't have to spend money to have fun. "Investigation" missions are a real highlight for some players, others hate them. Me, I loved them. A nice change from the quasi-medieval fantasy lineup; this is a game where you can shoot Cthulhu with a shotgun. Some interesting mechanical choices, not all of which work well, but some of which are pretty fun. Combat requires more movement and positioning than a lot of other MMOs. Also very focused on character-build options, but character builds are entirely temporary; you are expected to master everything on a single character.
WoW: Cartoonish or not, it's got art style, and sometimes writing. Has gradually gotten simplified over the years. Me, I don't touch anything Blizzard does anymore, because their insanely stupid positions on their "Real ID" idea convinced me that they are either stupid or malicious. I am aware that they have mostly finally fixed those problems, but their dismissive and insulting attitude towards complaints was a serious red flag for me. They waited for people to get hurt before fixing problems which had been clearly explained to them, and which frankly any ten-year-old could have pointed out, and they've never even admitted that the complainers might have had legitimate gripes. So I haven't touched it in years, and don't plan to.
GW2, Wildstar: I don't do business with ncsoft anymore, so I don't know. I've heard people say good things and bad things both about GW2, and Wildstar at least looks potentially interesting.
City of Titans: CoH spiritual successor, won't be around for quite a while, and honestly I'll be a bit surprised if they ever get anywhere, but if they do it might be the most interesting and fun, just from a game culture/design standpoint.