To be honest, I don't see myself going too nuts on this sale. I did that with last year's Christmas sale and wound up with a massive backlog I'm still working through, so I went in with a pretty small want list, including Rayman and potentially Trine 2, both of which I bought today. All I really have left is EYE: Divine Cybermancy and perhaps Driver: SF, and I think I'm pretty much good.
However, I did find a surprise must-buy: Crusader Kings 2 (One of the current daily deals). I assumed it was just some generic medieval strategy game until I found a couple of player stories on various forums that turned me around:
I remember a game in CK I had going as the Duke of Moray (who is the grandson of the historical Mac Beth, for those interested in history). While I was weaseling my way into the good graces of the counts of Scotland and taking land in Ireland, I married a lass from Byzantine and had a large number of kids. Not wanting my current heir (who was the son of the dukes sister) I changed the succession laws to favor my own kids. Good thing too, as Angus (my former heir) went a little crazy, killed his own infant child on orders from the voices in his head, and caught leprosy before falling catatonic. Meanwhile my own child became good friends with the king of England (who helped out when he later followed up on his fathers plan to overthrow the king of Scotland). Ended up with much of Wales, Ireland, the Isles, Scotland, Greenland, and surrounding under his banner as King of Scotland and Ireland, Duke of Moray.
I was playing the king of France yesterday and everything was going good for a while until some of my heirs died of the plague. My only heir and then subsequent ruler was, get this, a homosexual, heretic dwarf. After he became king he was quickly excommunicated, he never produced an heir, and then all my vassals revolted and split up France, eventually uniting behind some asshole. My gay dwarf character didn't lose everything; he hung on to one piece of land... until he died and my dynasty died with him.
So yeah, I had to buy it. And even better, there's just been a Game of Thrones total conversion mod released for it.