There isn't a best one, even if there were it would change every month, if not every day. Most antiviruses are 95% to 99% good (as in they catch and stop 95 to 99 percent of threats) it's catching the small remainder which makes the difference among products. You want to get the best main antivirus you can, but alone it's probably not enough.
Free antiviruses you can use are avg and avast, there is also a free product from bitdefender. the you need to give them some further support, have a second or third opinion scanner (like malwarebytes or eset online scanner) installed, both of these are free. These are NOT antiviruses, they don't do realtime protection, they won't conflict with your antivirus so unlike normal antiviruses you can run multiple ones. Something like malwarebytes or eset online scanner lets you scan with a whole different set of definitions, to catahc anything avg or avast has missed. You could install for example your primary realtime antivirus, malwarebytes(free version) and eset online scanner, your primary antivirus does most of the protecting, whilst the other two(which only run on demand) help you catch anything that does get through and help limit damage in those circumstances. You must NOT however run multiple primary antiviruses alongside each other, they will conflict and crash your computer.
If you are having a false positive problem then don't worry, just add the thing which is a falae positive to the "whitelist" in your realtime antivirus, and let it be detected by the second opinion scanners but ignore that particular result in the logs they produce, set the second opinion scanners to "prompt on detection" rather than automatically act if you are concerned they might attack a program you use.
You also will benefit from keeping windows up to date, in recent months there have been some problems with windows updates so don't let it be fully automatic, set it to check for updates but not install until you give it permission and MAKE SURE (set an alarm on your phone, set two maybe, set an alarm in your system tray using the task scheduler, write a reminder on a sheet of paer above your screen) to check manually every tuesday aswell and to install as soon as you have given it a few days for anyone getting crashes due to updates to become apparent. Keep up to date, but do it yourself, don't leave it all in the hands of your machine.
Another important thing for security is not to let browser plugins play automatically, in firefox you can set them all to "ask to activate" in chrome you can set them all to "click to play", internet explorer, i don't know how to do this but you probably shouldn't use that browser anyway. You should also at this stage fully disable or otherwise remove any plugins you don't use, and remove java aswell.
Another line of defence is to run an ad blocker and a script blocker in your browser, if you use firefox you can run noscript and adblockplus, this helps defend againt the modern menace of malvertising. Both of these extensions will mean you have to click a few things when you visit new sites to activate certain scripts and plugins needed for functionality but this increase in bother is more than outweighed by the increase in security.
A final tip, on the rare occasions you need to download new programs (exe files), save them, don't open them there and then. Then find them in your downloads folder and scan them with your antivirus and your second opinion scanner, then open a new tab in your web browser and visit virustotal where you can upload the file and have 50 different scanners have a look at it. Then after all those scanners have looked at it, check things like digital signatures and finally run it. For downloads of other file types, save them to a folder, don't open them there and then. Scan them with your antivirus and secnd opinion scanner but unless there is an exe file involved it's not usually worth sending these to virustotal aswell.
And always backup your data!!!! in multiple places!!!! which can be disconnected from your computer once you have backed up the files!! and which are NOT synced(it's better to manually backup at the end of the day, it takes a few minutes at max)!!
Edited by rp88, 01 December 2014 - 10:28 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB