Thee is no best and everyone and their great uncle is going to recommend one anti-virus over another. As to MSE, it's just a baseline scanner and needs to be used with a full fledged product. You would be better off with Immunet at that rate.
If you want a suggestion, I can recommend Bitdefender Free. I have used it and it's used on my parent's computer. I liked it because it was lightweight, cloud-based to help catch polymorphic malware (malware in the wild), and there isn't a bunch of fluff.
I personally don't use an anti-virus anymore and just use Sandboxie for my browser and scan all downloads at Virus Total. I do scan my computer periodically with different programs like Sanity Check, Stream Armor, FreeFixer, TDSSKiller, ADwCleaner, SuperAntiSpyware, and Herdprotec portable. Nothing is ever found. And I don't even use Windows updates. I might have four installed. Partly due to the motherboard and Sandboxie needing them.
By and large your best defense will be a periodic clone of your computer to an external hard drive. That way if catastrophe strikes you can clone back and it will be like nothing hardly ever changed. I use AOMEI Backupper for this myself and it's free. Store the external HDD in a fireproof safe. They can be had on eBay for as little as $35. Get one rated for electronics. And place the HDD in a plastic saleable bag. If fire strikes the inside of the safe will get moist.