Cody
Most of us here would suggest the free Malwarebytes for a once a week scan used in conjunction with the free Microsoft Security Essentials for real time free protection. Most here use that combination.
Microsoft Security Essentials is made by the makers of Windows and can be used only with Windows. It is not a one size fits all, like most of the others.
I have not seen one situation where computer problems were caused by Security Essentials. That cannot be said for most of the others.
In addition I would suggest WinPatrol, it is a pseudo Anti Virus, with many, many other good uses. It cannot be used alone as an anti virus, however.

Ihave noticed that you read my post, prior to its completion. Please be sure to read it all.
I will also say that Security Essentials has all the features of the pay for use Anti Virus.
Good luck to you.

I think the best way to explain my statement is that everything that the pay for anti virus software can do, Security Essentials does to.
Automatic virus definitions updates
Real time protection
User Friendly.
Bottom line. I dont think that you will find features in any other software that is not included with Essentials.
Even the Firewall. If you use Essentials, you can use the free Windows firewall (you can use the firewall with other A/V software, too.

You are very welcome.

Out of those two (Avast! and Avira), I would go with Avast! every time. I had to use Avira on one of the early leaked releases of Windows 8 as it was the only AV that I could get to work with it, but I didn't care for its interface, lack of update frequency and also because I couldn't password protect it (like I can with Avast!) to prevent unlawful/accidental entry to the program interface.