Here are the rules of the Steam sale:
1. Do not buy a game you want until the last day unless it is on a flash/daily sale where it is unlikely to be further reduced.
2. Are you actually going to play the game that you bought? Just because it's on sale doesn't mean it's money saved!
Bonus Autumn sale advice: The Christmas sale, generally the biggest of the year, is a month out. If you see a good deal now, snatch it up, just in case it's not in a future sale. That said, if you do miss, there's still a good chance it'll be in that one.
Bonus very good tjrp advice:
Feel free to discuss the games on sale, gauging opinions from people who have already played and so on and so forth. I'll update this post with any useful links, such as compilations of sales over certain periods etc."Buy the game if the price matches your idea of it's value AND you're likely to play it"
If you don't play it, it will ALWAYS be cheaper at some point in the future - always...
Personal Day 1 recommendations:
Daily - Darksiders 2 (and DLC) - 66% off. It's a good game, mechanically superior to the first, even if it perhaps has its own flaws and isn't as narratively interesting as the first. Still a good fun action adventure (bring a controller). [Note, DS1 is on sale for 75%. It may be off more, but it's unlikely. Great game, definitely play it before DS2 if you have the choice.]
Flash - Ends in 10 hours from post - Limbo (75% off) is generally well liked, haven't played it myself but hey.
- // Knights of the Old Republic 1 and 2 (75% off). KOTOR1 is an excellent RPG set in a great Star Wars universe. Good fun story, get to colour your own lightsabers. Haven't played 2, some say its better, some worse, all agree it's unfinished. Be sure to grab the community made unofficial patch/mod that fixes a load of content.