Same. Windows 7 Premium 64 bit, nvidia gtx 580, using 314.07 drivers. Updating them now, but might hold off playing until I see some response here.

Played the day the expansion was patched with no problem. Hard crashed twice in a burn party. Seemed to be when people were casting buffs. First time I got a "graphics driver crashed" message. Second time my entire computer crashed and needed to be restarted completely.