There's been a huge abandoment of the subscription model over the last few years. MMOs that started as traditional subscription model games have been rejigged into the free-to-play model where players don't have to pay to play, but instead are offered 'products' such as experience potions, pets, mounts, and in some cases power enhancements.
The beauty of this model is simple, if you don't want to pay a cent to play the game you don't have to. There may be some inconvenience; it takes longer to level; forsaking fast travel; even not being able to go into some zones; but you have a choice. And it's great for budget challenged players.
There are advantages for the developer too. If the game is anywhere past decent, it's a chance to aquire new players, and with each new player added there is a chance to increase revenue with in-game sales.
So the question is: What games, past, present or future, would you like to go free-to-play?
For me, I'd like to see Asheron's Call converted to free-to-play. How about you?