Good games on steam for decent PC?

I recently got steam and am wondering wat are some good free games to get. My pc is pretty decent at running games. I ran minecraft, unturned, portal and they all ran pretty smooth. So i'm wondering wat are some good free games and paid game that are good. Thanks

Fyi: I like games like the elder scrolls series, fallout, dayz, battlefield, and tomb raider.
I don't like mobas, rts or turned based combat games

Bioshock Infinite is fantastic, and is separate from Bioshock 1 & 2 if you would like to give it a try. Portal is also great. Half Life is a classic, and will help you understand a lot more internet jokes. FEZ is an indie puzzler that is also great. Mark of Ninja is another good indie. Assassin's Creed is a big series that can keep you busy for a while. Batman Arkham City is also a really good one.

I had never joined Steam until they were developing Steam for Linux (which is what I normally run at home). So the first any-OS game I tried was Team Fortress 2. It may be cartoon like and not politically correct, but it is free, runs the Source Half Life 2 engine, and has been popular for many years of updates. Although, to get the best drops or to trade or sell things in the Steam Market you have to buy something (most anything at least once) in the in game Mann Co. Store.

If you think you have done everything in minecraft, you may want to check our the Technic Launcher that as all sorts of modpacks, including Tekkit which is popular. That adds all sorts of machines, mystical things and places, and you can even go to the moon and mars. It has NEI showing in game recipes for most things. http://www.technicpack.net/download