Well, the Steam sale is proving to be a reliable source of great deals to the surprise of - oh, wait - nobody! Anyway, here's my picks from today's bargains. As usual, links go to my reviews, where applicable.
Divinity II: The Dragon Knight Saga: $9.99 - This game is a tremendous amount of fun. I have yet to finish it, but I have certainly been enjoying it. The amount of stuff to do and the snappy, sarcastic dialog choices are wonderful. At that price, even if you don't finish it, you will get more than your money's worth out of the game.
Fable III: $24.99 - A solid deal on a solid game. While not the deepest or most complex RPG experience you'll encounter on the PC, it is a very enjoyable and satisfying one, and the Industrial Revolution-meets-fantasy setting is a nice change of pace from typical RPG settings.
Dungeon Defenders: $7.49 - A friend of mine gifted this to me a short while back, and I've been playing it with him fairly regularly. It's a really fun game. The cartoony aesthetics sit on top of a remarkably satisfying monster-bashing experience. Play it in co-op, if you can.