Hey, Slynky
I'll chime in here, sure.
My first MMORPG was Anarchy Online, a science-fiction MMORPG set 30,000 years in the future.
Humanity has fractured into 4 separate species, and Homo Sapiens is no more, although Homo Solitus is basically just Homo Sapiens with a few bio-engineered changes to allow the use of nanobot technology. I'll resist the temptation to talk about the game in exhaustive detail.
A friend was beta'ing the game, and talked to me about it incessantly. I was heavily into FPS games at the time, specifically a Team Fortress mod for the Quake 3 engine.
Anyhow, by the time the game launched, I was ready to try it. I created my account on June 30, 2001 - the day of retail launch. I am still playing today, although I took a sabbatical from February to October of 2006. Call it 60 months of continous play.
I have over 5,700 hours logged on my main character (or "toon"), Francesca "Hildegaard" Harrist. Hilde is a female Solitus Doctor.
OK, about the phenomenon of the MMORPG.
Approach it cautiously. When you sit down to play in the evening, set a time limit for yourself, an absolute dropdead I-will-be-in-bed-by-midnight type limit. If you fail to do this, you will find yourself playing until dawn, neglecting RL, and generally allowing the game to dominate your life to an unhealthy degree.
The problem is than a good MMORPG (not all of them are good, not even close) is immersive to a degree that defies description. Furthermore, a well-designed MMORPG rewards those who invest more time in the game.
There are a lot of crippled people in the MMORPG world. Crippled physically or emotionally. People like that need an escape desperately, and the immersive online world permits that escape. Even if your RL body is confined to a wheelchair, online you can be the hero of your dreams, slay foul monsters, rescue fair damsels in distress, etc.
When I first started to play AO, I was one of those cripples. Basically, I came home from the dentist's office one day to find that someone near and dear to my heart had put a gun in her mouth and sent herself on to a better world. I needed a place to hide. (No condolences please, this was years ago, and I've dealt with it).
Now, this does not mean that a normal, emotionally healthy person cannot play MMORPG's, play them well, and have fun at it. It just means that the online world contains a percentage of people who spend most of their waking hours there. The only way to compete with these people is to become one of them, and if you have any sort of a life, you don't want to do that.
The trick is to take the game on your own terms, do what is fun for you, and log out whenever it starts to piss you off badly
Don't compare yourself with the hardcores, or measure your success by their achievements.
The other SF MMORPG I can reccommend is EVE, which I played for the ~6 months I was on sabbatical from AO.
As far as the "traditional" or "medieval" MMORPG's, I can't say. I don't do elves and dwarves, man