Saw another thread where they talked about doing your research to find the best deals during Steam Summer sale. Hopefully many of you already know of it, but in case you don't, I wanted to introduce my best friend and worst enemy IsThereAnyDeal.
You can login with Steam to sync your wishlist, view historical price information for points of reference and to gauge how frequently a game goes on sale. You can also set criteria of when to get notified when a game lists at or below your target price, and even specify vendors if desired. I definitely recommend it to all my fellow gamers.