After the update last night, my brightness is way off! Where before I could place a torch every 14 or so blocks, now I'm down to only about 5 or 6. I have brightness set all the way up in settings and still way too dark. Also tried to change the gamma in the options file, but when I start the game it reverts to 0.
Recommend you vote for and comment on the official bug, so it maybe gets more notice. And if you find a fix (updated drivers perhaps), post it here and over there; you'll help a lot of people I'm sure.