Path of Exile - Diablo 3 type persistent world
Not sure if this has been mentioned, but Path of Exile is now in open beta. http://www.pathofexile.com/
You can choose one of six classes, with choices ranging from Ranger, Duelist, Shadow, Witch, Templar, Ranger, and Marauder.
Got in a couple of hours last night, playing as a marauder, and the skill tree is quite extensive. I chose to go 2h route with a splash of health bonuses.
Check out the skill tree: http://www.pathofexile.com/passive-skill-tree
Itemization follows the standard route these types of games has us all used to, with one minor exception. Items have gem slots, and these gems contain specific powers that also level with usage.
The download/Install took about 90 minutes and went smooth.
Overall I enjoyed myself, and just scratched the surface of the game. It appears to have ladder PVP rankings and such, but as of yet have not touched any of it.