On top of what people have suggested, maybe additionally also the Kaspersky Rescue Disk.

http://support.kaspersky.com/viruses/rescuedisk

Either burn a CD-R(W) disk with it, or to a removable USB device. This is just a backup for those cases where it seems some malware is causing your normal Windows antivirus software from functioning correctly. Then you can boot from this rescue disc and scan your Windows system with it. No malware can affect its operation because it loads to a Linux environment from the disk in order to scan the Windows system.

If you are connected to internet, it will also download the latest virus databases before scanning, so you don't necessarily need to re-burn the Rescue Disk just in order to get the latest virus definitions.

I recall this was quite handy when one of my PCs was infected badly by some trojan (Security Sphere 2013 or somesuch) which IIRC blocked my normal antivirus software from functioning correctly. It couldn't do the same to the Kaspersky Rescue Disk. In the end though, the trojan (ransomware) was so persistent that it had to be removed manually by some instructions from the net. Fun times.

EDIT: Then again, it seems the development of that product has ended (ie. they are not fixing bugs in it anymore, if there are such), but they are still releasing virus definition updates for it, so I think it is still fully usable.

We're using Avast on one PC and AVG on another. Doesn't appear that anything has gotten through either one, but we also don't tend to visit sites where the really nasty crap is found.

Malwarebytes, of course.

Good idea on the rescue disk, timppu. One other thing in my recovery toolbox is the ESET online scanner:

http://www.eset.com/us/online-scanner/

I suggest nothing. From my experience there are 3 sources of malware these days: ads, pirate software and those which come bundled with legit software. For the first one I recommend adBlock (Firefox)/uBlock (Chrome) as a quick easy solution. You can also try learning to use NoScript/PoliceMan/RequestPolicy (Firefox) or uMatrix (Chrome). For the second one try to find some free (open source) alternatives or at least some trustful crackers in case you have no free alternative. As a solution for the last problem I recommend Softpedia. They usually have details about any other software bundled with the program or any unexpected modifications which the program you're about to download will make to your OS or browser.

I also recommend nothing. I've rarely ever had issues with viruses or malware, course i'm very selective what i put on my computer.

Adblock & Noscript heavily removes anything that might run in the background on tainted sites.

Course OlivawR (Previous post) mentions this already :P

I think the last Malware i encountered was on my GF's computer where she accidentally activated something she shouldn't have. It looked like an official M$ program and telling us there was issues, but when i logged into an alternate admin account those problems were absent (but was as good a time as any for a backup). A little Googling and searching, and then modifying the registry and killing processes manually, and the problem went away. The malware was far blackmailing you or it would destroy your desktop icons (and start menu) if you didn't pay, and any non techies wouldn't know how to get around it's stupid auto-close features for the task manager...

Actually the best protection you can probably put on your computer if it's Unix/Linux, is simply don't run a privileged account. Same for Windows (XP and on), run with non-admin access. Yeah you can't use your CD burning software easily and some games don't want to work but the virus/malware can't infest deeply into your OS.

That's a preference. :P
Some people like having an antivirus even if it's just reassurance.

The problem with saying "I haven't had issues with malware" is because for many types of malware, the idea is to stay undetected. Ransomware is different, of course.

I too use Bitdefender Free, moved to it from Avast which had morphed into a resource hog lately. Also, I run Firefox within Sandboxie and Adblock Plus is a must addon in my opinion as well. Then, Malwarebytes on demand when needed and for regular just-to-make-sure scans.

I've been using Avira for years without problems. However, there's a bug with their popups that can potentially cause performance issues. You can use this program if you don't want popups:

http://bgpkiller.weebly.com/

Avast has a good detection rate, but seems more bloated/resource heavy than Avira to me. MSE is ok if you use a lot of common sense while browsing and uses the least resources, but has poor detection rate. AVG I would never consider using, IMO it's garbage.

The best protection against virus is common sense!
I don't like security software, but when I am bored enough to install one, it usually is either avast or avira. I find avira less annoying and more likable.

I'm not using any common antivirus, but a combination of MalwareBytes, AdBlock Plus, Bootkit Remover, NoScript, MBRCheck, TDSSKiller, <i>Dr.Web CureIt</i> (a standalone antivirus), and a software that I designed myself a few years ago...

I programmed a very useful utility, that takes snapshots of all system files and registry entries (easily customizable), and compares them to the previous ones. Within a minute, I know exactly what changed (including CRC changes, files versions changes, added, deleted and modified files, etc.). It saved my ass once, and let me manually get rid of a new malware that was not detectable by antiviruses at that time. It only took me 10 minutes to identify and remove it.

I use to manually get rid of all viruses and malwares outside Windows (through WinPE or Knoppix). I track and remove them manually from here (MBR, files and registry), including botnet and MBR rookits, keyloggers, hijackers, backdoors, rogues and ransomwares. I can assure you that all the antiviruses have difficulty to remove those nasty ones. I'm an IT technician and I owned a computer business for 18 years until 2013.

Antiviruses are only good for intercepting viruses before they get to your system. Once you're infected, they are sometimes too sophisticated, taking the control of the antivirus, which make them almost impossible to remove if Windows is running. Think of them as vaccines, and not as magic solutions!

Linux FTW!

The software is still alpha, but fully functional. I made it several years ago and never had the time to complete it. Everything is working perfectly and the software never crashed, but there are still some missing parts (e.g. new buttons that were added during the development, but don't do anything when you press them and two incomplete dialog forms that were partially implemented). Removing them would only take a couple of minutes... Now that I have a bit more time, I'll probably remove them, tweak the software a bit, then give it for free. I'm not willing to release it in its current state, though...

I also started to work on a fully redesigned version of the software, with a much better interface and more useful functions, but I had to stop its development because I had no more spare time... I'll probably give it another shot in a near future, then release it as a freeware for IT technicians.

I've attached 5 screenshots. The first one contains different windows from the current build. The other ones are just work-in-progress screenshots of a possible upcoming release (there's a lot of things left to do!).

I used Avast (free edition) back when I was on Windows, it never gave me any trouble, has good detection rates and I've installed it on countless computers. Would highly recommend it.

For some added protection I also use the addon 'Ghostery' for Firefox.