WireHead: Man, I really love GOG for their same-price politic! I would be interested in trying out LA Noire, the complete edition, but it's really a total rip-off to european customers!
I heard something about some problems with the DRM involved, but I've yet to research more about it, so that, coupled with the 1$=1€ Steam politics and my backlog, means I will resist to impulse buy this... 75% discount will come again in the future (I hope!), who knows, maybe with some luck the game will end up on GOG somehow, sometime!
It keeps hitting steep discounts on Amazon, Steam, and elsewhere, this won't be your last chance to pick it up for cheap.
XBLA (gold members): Shoot Many Robots 50% (400 points), Trine 2 50% (600 points) Gotham City Imposters 50% (600 points) and some other games that no one probably wants (Nexuiz, a Worms game, X-Men).
Open to everyone: MS Sale on full games, these are downloadable titles of older games that were out for full disc retail but can be had digitally, they are all 5 USD:
Alone in the Dark
Perfect Dark Zero
Bomberman
Blazing Angels
Tom Clancy's GRAW
Open Season
Disney Bolt
Tornado Outbreak
Cloudy With A Chance of Meatballs
Viva Pinata Party Animals (the worst VP game, btw)
Surf's Up
Virtua Tennis
SEGA Tennis
Rockstar Table Tennis
FaceBreaker
Dark Void
PoP: The Forgotten Sands
Conan (way more fun than it should have been)
Kameo
A lot of these have downloadable demos available on Live, so you can try them out before buying. The 5 USD sale has been up for nearly a week, dunno how long it'll last.