What is Reddit's opinion of ThreatFire?

From 3.5 billion Reddit comments

Avira has a free version that's lightweight, and last I checked, has the highest detection rate in the industry.

I also like Threatfire for supplemental, real time anti-malware protection, and it plays well with other security apps.

If you want to go tin-foil hat with your security then install: Threat fire and Peer Block along with your anti-virus (I use MSE, it's fine) and your firewall (I use Comodo)

Edit: i forgot Spybot S&D

I've been using it for two years now. It's nice because it offers you protection without having to do any sort of active scanning. So it doesn't slow down your system. It learns how you use your computer. It picks up on your habits and your personal style so to speak. It's known as behavior based protection. It's the only way to protect yourself from a zero day attack. Virus scanners need to be updated every day. But if there is a new virus out there and it's not in the virus scanners database you're completely helpless against it. But threatfire will pick it up. They give a great break down on their site here. It's the ONLY way to stop a zero day attack. Antivirus programs are completely useless against zero day attacks. You need to have it for complete protection.

I would recommend Avast and as additional protection ThreatFire (both are free !). Thats a good combination and with a little common sense you should never have any problems with viruses what so ever :)