2012, easily.
2010 was fun, but honestly, overrated. They had awe inspiring physical ability but they were often sloppy and undisciplined, didn't have much perimeter shooting, and benefitted from a kind of fluke easy schedule (the 2 big non-conference wins, UConn, and UNC, came against teams that missed the NCAA tournament that year). They also won a ton of very, very close games. 2012 just didn't play many close games, and got no major breaks in their tournament run but closed the deal anyway (despite how tight Cal's butt got in the 2nd half of the title game).