Steam Multiplayer Recommendations?

Just getting into Steam (used to rock the 360 for Halo:Reach instead) and am looking for multiplayer games.  What do you guys play?

And, if anyone wants to add me, my tag is the same there: remption.

http://steamcommunity.com/profiles/76561198049942699/

Here's a Few that I play on a regular

  • Killing Floor (this game is just a Survival Horde Mode game awesome fun to play with friends)
  • Speed-Runners (This in my Opinion is a mix between Mario Kart and Super Smash (sort of) see some gameplay you'll see what i mean.
  • Sniper Elite - Nazi Zombie Army (If you miss zombies on COD)
  • Borderlands 2 (this is self explanatory if you've played it with some friends.

Team Fortress 2- Free. Best online FPS ever IMO. 

Counter Strike Source/Global Offensive 

DayZ

Rust

DOTA

Many more haha

I've been playing a lot of Red Orchestra 2 lately. It's a really challenging and uber-realistic WWII fps. Reminds me of COD2 (one of my favorite games of all-time). It's definitely not for everyone as it has a huge learning curve, but if you have some patience it's super fun. 

 And Payday 2 for some fun co-op play with the homies.

You could also try jumping into MMO games such as Rift, Everquest 1 or 2, and project 1999. All of these are free.