PCI x16 slot options?

[lucasburns]

my new pc is mainly used for gaming and i want to know what would be a good option for the other 2 PCI x16 slots? i currently have one filled with the EVGA SuperClocked 02G-P4-2765-KR GeForce GTX 760 2GB 256-bit GDDR5 graphics card. should i crossfire and get another graphics card or is there some other option for those slots that would be good? also would it benefit to add another graphics card or possibly another two?

 

[i7Baby]

You should keep the x16 slots for graphics cards. SLI another 760.