This is basically me, in web site form :D
http://isthereanydeal.com/

This site is fantastic. It tracks all the major digital games sellers and lists all games on sale according to filters you specify as well as allowing you to view the previous lowest price of any game.

As well as that, it can import your Steam wishlist and you can set a desired price you'd buy the game at. The site will then email you if it becomes available for that price from any retailer!

It also tracks Indie bundles and games supplier discount codes.