Minecraft in my opinion is better than New Vegas, but then again, thats my opinion. And graphics aren't everything. New Vegas has REALLY bad graphics, compared to other games, and I still play it. I even play Minecraft because I dont care about graphics.
Gameplay is the only thing that matters, and so far New Vegas has better gameplay than Fallout 3.
Agreed, graphics don't make the game, the gameplay makes the game, who'da thought it?
In my honest and humble opinion, Minecraft completely outclasses pretty much all of the new CoDs, Halos, and... all those other games that rely on graphics to sell a game that has almost no significant new gameplay over its predecessors.