I've played or beta tested many MMORPG's.
Asheron's Call - Great game back in the day, interesting leveling system, skill based. You created spells by mixing components rather than just getting scrolls/spells at certain levels. You got exp for doing your skills rather than killing monsters. Unfortunately combat bots, poor ai, and its poor graphics ruined the game. Had great gameplay mechanics.
Everquest - Level based system, kill mobs get exp. Interesting dungeons, immersive environments, hard and difficult. Overall this was probably the best RPG game due to the immersiveness of the environment/character.
DAOC - Don't remember, beta tested it for a few weeks. All I remember is the graphics were above the other things out there, but the game was completely linear. You fought these mobs at lvl 7, fouight these mobs at lvl 8... They just huddled in groups and didn't really roam or anything. I'd say this is the start of where MMORPG startted to take a different turn to the worse. Not at all immersive, felt mechanical.
Asheron's Call 2 - The first to really make skill trees, took the ideas of DAOC and made more character development. Didn't really take all the concepts from Asheron's Call, but instead made a hybrid of it with Everquest/DAOC.
EQ2 - Built upon the previous, made it easier but tried to maintain the immersive of the environment/character, but in the process made th game feel mechanical in nature. Didn't really work out. You can't use immersive and easy in the same sentence. They wanted more immersive character combat, so what they gave you was about 10+ buttons in your toolbar to mash during combat, so instead of watching the fight, you are watching the toolbars light up to see which button to mash now. Basic mob AI, they run towards you, attack until its dead.
WoW - See EQ2, just a little different feel, made it easier, graphics was interesting but not necessary "better." I just couldn't get into it. It just wasn't fun to me. Nothing drew me in.
Dark and Light - Only played it once for about 10 minutes. It crashed and I never got logged in again. Avoid.
Vanguard - A clone between EQ2 and WoW. A bit slower on the toolbar mashing compared to EQ2 but still not great. Had great potential but the unreal engine port was not good, and the game engine was flawed.
---
All in all, Asheron's Call and EQ were my favorites, but they are old and obsolete now. I currently play EQ2, and I'm having a decent time but it took me awhile to "warm up to it." I do wish they fixed the hotbar mashing though and the game would be a ton better.