With Toontown closing in September, I started feeling all nostalgic, remembering the fun I had with Toontown, and other MMO's. This thread is dedicated to nostalgic MMORPG's.
Wizard101: 
Wizard 101 was a game I played alot when I was around 8-11. The game had a pretty good soundtrack as well. The combat had this Yu Gi Oh-esque combat in which you would pick a card with an elemental monster on it, and when you select it, you would cast the spell, and the monster on the card would rise up from the ground and perform an attack on your enemy. It was pretty fun, and I enjoyed it. However, there was one point where if you reached a mission, you would have to be a paid member to continue with the story. So that was kind of a bummer.
Pirates Online: 
Pirates Online was created by the same people who created Toontown, and it will join in closing on Septemer 19. I believe it had real-time combat, in which when you click, your character would swing its sword. The game also had some pretty cool ship combat, and I had fun with that. Much like Wizard101 though, one problem was that when you got to a certain mission, you would have to pay real money to continue the game. So that sucked.