MVPS Hosts Files , Avira Free ( or Panda Free AV ) and Windows Firewall with Advanced settings.( there are several tools you can use to control Windows firewall.)
Kaspersky is good but complicated, too many settings and there are free products with equal or better detection rates.
Win Defender is baseline protection at best, Microsoft tell you to find a 3rd party product.
I find the new Malwarebytes causes too much lag on both system and browser, I keep it as an on demand tool.
Edit because I managed to leave half the reply behind.
My son has Win7 desktop, Win8.1 64Bit Laptop , I have Win 8.1 on 2 laptops and a desktop, this is what is in place and works perfectly.
OpenDns , CryptoPrevent (set and forget settings), Malwarebytes Anti Exploit, MVPS Hosts Files, Avira Free , McShield (free) for USB protection.
never see any real lag/delay and his systems remain clean and safe.
You don't give system specs or say what you use the system for......... 90% of security is common sense, if you are living dangerously visiting bad sites then you need more armour.
Edited by Andrei_V, 26 April 2015 - 04:38 AM.