I use Avast! free, with periodic scans by MBAM (Malwarebytes antiMalware); with Windows for firewall.
Also WOT plugin to Chrome to reduce risk of visiting dodgy sites.

I do find MBAM sometimes reports things as bad that I consider acceptable and would be irritating if I allowed it to fix them (some cookies in particular).

I find MBAM particularly useful when a careless install from some download inserts dodgy toolbars and search engine preferences.
Avast! and most other AV products don't try to address those.
That is usually when helping out less technical friends, but I am not 100% clear of falling into that trap.

On computers that are just used for browsing and maybe work processing I tend to use Microsoft AV;
it does less well in most reviews but has never let me down in those simple situations.

In reply to a post by trolleybus:

I have no doubt that any AV product will do what it says on the tin but surely the effectiveness of the product is more to do with the frequency/speed that updates are pushed down to update the product. When was the last time you noticed your database changed?

Mine is updated every day (that's MSE). I would expect any other AV program to be the same.

In reply to a post by kasg:

Mine is updated every day (that's MSE). I would expect any other AV program to be the same.

Indeed - sounds like some people on here are a bit paranoid and under the 15 year old impression that having no AV means the computer will immediately get infected. I have Windows Defender on all my machines and don't have a problem.

Daily is quite irregular in my opinion. Other solutions will check for updates every few minutes.

In reply to a post by ukhardy07:

Daily is quite irregular in my opinion. Other solutions will check for updates every few minutes.

Check for is completely separate to number of updates issued in a day.

The big vendors normally only issue one update a day, unless there is a big issue in progress, then you might get 5 or once I saw 8 updates in a day. Unless you have a corporate contract that gets updates every 15 mins, but those are not tested in advance.

Avast free is Anti-Virus, Malware Bytes is anti malware two differnt infection sources. Have tried them all over the years and am now running Avast coupled with SuperAntiSpyware with occasional scans with Mbam. Never had an infection problem.

I believe most AV products, free or otherwise, will update as and when required.

I never allow any programme to update automatically and that includes any MS product.

I usually update the AV prog' at least once a week.

I repeat, no issues in over 10 years. It's usually the dodgy websites that users visit or opening emails with attachments so mainly user error and not necessarily the AV that is at fault.

In reply to a post by jchamier:

Check for is completely separate to number of updates issued in a day.

Indeed, I was not referring to how often it checks, but how often it actually updates.

Norton had a bad rep for years because it behaved like a virus (difficult to remove without having to format your HDD) and was notorious for slowing systems to a crawl. Then, around the mid 2000s, it suddenly got much, much better. Norton finally got a clue. But I think it's taken a bit of a downturn over the past two years. It performs very badly on older computers (by older, I'm talking about a couple of 2009 laptops I own). It performs great on my much more recent and powerful desktop though. I still find it unusable on that though because the full screen detection which is meant to stop it from scanning (in case you're watching a movie or playing a game) doesn't actually work. I can't tell you how many times I had games crash because it decide to start doing a scan due to inactivity. So I eventually just dumped it in favour of Kapersky which doesn't seem to have any of the above problems.

Nobody using Linux ?