One such title that's been flying well under the radar is Xsyon, an upcoming post-apocalyptic MMO from Notorious Games. The game is scheduled for an April 15 release, with plans to allow pre-order players to begin the game in mid-March. Xsyon's official site is very well done, offering backstory, screenshots, and extensive information about the game itself. The recently added forums rounded the site out nicely, opening the doors for discussion among players anxious for the game to arrive.
While the graphics aren't as perfected as bigger name games, the features are where this game really shines. Xsyon will be released in a series of installments, growing in every direction (landscapes, skills, crafts, etc.) as players learn and explore farther. So this means players will directly affect the world and the direction of the game by their actions and choices.
Xsyon is a game well worth looking into -- check out the official site for the full story.