It's a fair, hardcore fight!
I voted: Kaspersky Internet Security.
Let me explain a little the scenario and what I would do.
First; read this:
How to choose "the best antivirus"?
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Now you've realised any top notch security software will protect you the same if you're conscious while surfing and downloading, it's time to see what do you need for your specific system.
Here's a quick helping hand:
What do I want?
My hardware is good and I want an interactive/customizable software:
Kaspersky Internet Security
My hardware is good and I want an independant software that's smart enough to decide for me:
BitDefender Total Security
My hardware is not that good and I want a customizable software that lets me decide about events:
ESET Internet Security
My hardware is not that good and I want a software that's independant and smart enough as to decide for me:
ESET Internet Security default settings
My hardware is good and I wish to ruin my online experience and bug my whole systen:
Any Symantec product
Disclaimer:
The aforementioned suggestions apply on the majority of the cases, nevertheless do not trust my word on its whole. Each system is an universe, and despite Kaspersky behaves light on my system, it may slowdown yours. Use the free trials of the programs to see how they work on your computer, and make sure to never run two at the same time, uninstalling them and cleaning the registry every time.