For those who want recommendations, here is a little info about some of the best games listed above:
1. Guild Wars Trilogy - While the most expensive, Guild Wars has zero monthly fee and an enormous amount of content. If you have $40 and are not sure what you are going to use for gaming this summer, Guild Wars is an incredibly large game with hours and hours of PvE and endless hours of highly satisfying PvP (especially if you join a guild and get into unlocking skills/characters). GvG is where this game absolutely shines - especially if you find a "fun" guild that wants to do well but is more focused on playing a LOT instead of only playing a few times/week while ensuring wins with perfect guild groups.
2. City of Heroes: Architect Edition - If you haven't played CoX, then this may be worth a try. While the game can be a bit of a grind in higher levels and there is not much variation in gameplay, new players will definitely not get bored before they get their $16's worth. Incredible costume customization and a fun battle system as well as a refreshing MMO theme make this worth trying.
3. Age of Conan: Hypborian Adventures - The graphics and gameplay are top-notch. Unfortunately, at launch they only had about 40 levels worth of content that could be pushed through in 2-3 weeks. I've heard that this has not been remedied completely yet, and that the PvP game at top levels is completely destroyed because the class balance allows for one-hit kills. Plus, guild cities are not worth the effort involved to create or the effort involved to attack or destroy them. There is not an endgame worth mentioning. Purchase this as a super high-quality budget game you expect to play for only a month and you'll love the $10 you spent. Expect more and you'll be sorely disappointed.
4. Pirates of the Burning Sea - If you enjoyed Sid Meier's Pirates, then you'll enjoy the combat in this game even more. It behaves in the same way for the ship battles but you have the added benefit of playing with others. It is the same thing over and over and character growth soon becomes too slow to break up the formula, but it is definitely worth the $16 if you approach it as a great one-month title and not an MMO you have to marry for a year.
I might buy EQ2 Shadow, since I still haven't bought the expansion.
If you like playing a game and really playing all of it then EQ2 has an interesting option. You can turn off experience completely, and then turn it back on to level. That way you can play all areas at all levels without the content becoming trivial.
What are the benefits to doing that? For one, you can get Achievements (character benefits) without leveling. Your character becomes quite powerful, and so you can take on harder and harder content. The harder the content cons to your character (and you win the fight), the better the loot becomes.
So, you end up with lots of loot drops and the ability to take on content intended for groups ... but all by your lonesome. Or, with a small group that does really hard content.
We play this way exclusively now, and its really made the game fun again.
Trazzlo - Are you retired or independently wealthy? I can't imagine playing all the junk (or even traveling to it) in EQ2 while working full time.
Well, its about the same junk as you get in every other game, but a lot more of it.
We just play slowly ... it's been about 4 years so far and we still don't have a single character over 55. But, we do like just puttering about, and playing all of the zones rather than just grinding through as fast as possible, while only seeing about 1% of it.
Some people like that way of playing, some hate it. What we like is that there is never a shortage of things to do, or new places to see or quests, and they all pay off in terms of drops and challenge.