I've been using the following site for some time now and it's brilliant for seeing current game deals.

http://isthereanydeal.com/

I used to visit all the game bundle offer sites weekly to see what was new or if they have updated, but with this site you can see most offers all together in a single list. Very useful.

If you register an account on the site it also has a brilliant library feature, allowing you to link your Steam, Desura and Gamersgate profiles (to create a list of the games you own, plus connect to GOG. Very useful.

You can also create a waitlist, which is basically the same as a wishlist for future purchases so you get alerted when a game on your list comes up on offer.