There is no "best" but there are a number of good ones. Eset is fine. I'm a fan of Kaspersky and use it on all my systems along with MalwareBytes Professional (as well as SpywareBlaster and WinPatrol). There are a number of decent free Anti Virus apps, but I'm old school and believe you get what you pay for. When it comes to system security I won't "cheap out". In the end, "smart computing" is at least as important as the protection software you use (don't visit "iffy" sites, don't download anything unless you are 100% certain you know what it is, ditto opening email links, create frequent disc images or backups, etc).