Firefall (like CoD + WoW fusion)
PlanetSide 2 (open world shooting, with 3 FPS on the most Hi-End Gamer PCs)
Combat Arms (basicly like CF, but much better)
Ghost Recon Online (tactical shooter, but the optimization is in the cow's ass)
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Also some good games for Multiplayer:
Halo Custom Edition (servers still working after 10 years, with hundreads of servers, and thousands of players / day)
Halo 2 (but the servers are abanoden, and wil be shut down soon, but with friends and a LAN party )
AVP 2010 (pretty good, if you learn how to play... very annoying when you don't know how to play [not so easy, trust me])
Crysis Warhead