I've played a few....here are my opinions...
Guild Wars - if you don't want to pay a monthly fee, go with Guild Wars; frequent expansions, Nice graphics....it's a pretty good game. However, it -is- free for a reason, and I don't feel it has the same long term appeal as some of the other subscription games. In all...it's a poor man's lineage. Guild Wars is pretty, but when it comes down to it, I want a little more than ‘pretty’….but that’s no reason to turn away; Guild Wars looks good, seems to release new content and expansions faster than you can buy them, and is well worth a look if you’re not wanting to pay a subscription fee….if you are willing to pay to play, then have a look at an upgrade…
Lineage 2 - For a long time, Lineage 2 was my favorite game....why did I stop playing? Because of the free pvp. Never buy a game that has free pvp....why? Because sooner or later you'll end up in that 'low level, high level' crossover zone, and some high level wazzock will find it funny to go out of his way to one-hit you, laugh, and run off....no reason, just to be a smeghead. Death in Lineage was far too expensive (massive exp loss, and potential drop of gear, up to and including your currently equipped weapon/amour) for this to be justified....PKers killed Lineage for me, and I don't intend to go back. It was a good game in its day though…it’s probably the prettiest MMORPG on the market, with a massive selection on nice looking armor, weapons, raid bosses, and so on….but honestly, the world is pretty small by MMORPG standards, and the odds of you making it through the low levels without being ganked are next to 0. You’ll lose gear, levels, and time far too often, and just be driven to frustration.
City of Heroes/Villains - Fun, but a little dated. Extensive character customization though...far in excess of any other MMORPG on the market (that I know of). Soloing can be a little difficult at times, but it’s still a fun little enterprise. While I don’t believe that CoH/V is the –best- on the market, it still is a very good game, that I don’t really find any fault with it. My only real turn off was the absolute lack of RP that went on. If all you want to do is fight, fight, fight, then CoH/V is worth a look (P.S. City of Villains kicks City of Heroes in the marbles).
Lord of the Rings Online – Bought it, played it, wasn’t impressed. However, it’s far too early to be writing it off. The Game is still young, and there’s still a lot of content to be added…but, thus far, it was the least enjoyable MMORPG I’ve played. I’m keeping my account with it though, just to give it a sporting chance later when there’s some new content added.
World of Warcraft – There are three types of people in the world….those who love WoW, those who hate WoW, and those who have yet to play it. For people who have been introduced to the game, there simply aren’t any neutral stances…I happen to be in the majority camp that believe it is, by far and away, the best MMORPG on the market, and will likely continue to be so. While there are some things I find at fault with WoW, the fact is that the game has provided me with a great deal of fun and enjoyment that far outweighs whatever personal gripes I may have.
The game world is absolutely vast (larger still since the Burning Crusade came out, and with the likely addition of a new continent in the next expansion), there are many playable races with their own distinct character and flavor, many different classes that can be specialized to do very different things (a Holy Paladin and Retribution paladin, although the same class, will fight in a very different manner, for example), two distinct factions with their own storylines, cities and characters, optional pvp (on non-pvp servers) so you won’t be endlessly ganked by high level wazzocks….WoW simply offers more than anything else that I’ve yet encountered.
Obviously, nobody is going to be completely happy with it…but I can honestly say that I have yet to hear an argument from the ‘anti’ camp that I really agreed with, or that I felt was strong enough to make the game either not worthwhile, or not fun to play. WoW is what it is: the market leader, and I believe it is worthy of its reputation as being the best in the field.