I find bullguard is good although it is not free.

For me the order goes Avira Antivirus, AVG, Microsoft Security Essentials, Avast, all the rest (which are the ones you shouldn't use). AVG was always my preferred anti-virus from 1998 to about a year ago. Then I decided to try Avira and I feel it has a better positive detection rate than AVG. AVG does signal some false positives as already pointed out and sometimes it misses things. MSE is actually really good but I prefer Avira due to familiarity. Avast is good as well but I find the UI hard to work with and too graphical for it's own good.

My recommendation: Avira Antivirus (http://download.cnet.com/Avira-AntiVir-Personal-Free-Antivirus/3000-2239_4-10322935.html)

Malware Bytes it good but it's only a remover.

http://www.malwarebytes.org/

For spyware I use Spybot S+D.

As about everyone else has said - AVG.
I have had 0 problems.

hmm i didnt do anything, i just restarted my system and everyhting was fine :D but thanks guys!

I've tried both Avast and AVG and weren't too happy with either. I'm currently trying Comodo and I'm happy thus far, its faster, doesn't lag the processes as much when scanning and it catches a whole lot that especially AVG doesn't.

Is it really that good?

I was going to recommend Avira...

It's very close- they're both excellent, unobtrusive AVs. The MS one just shades it for me as you don't get a daily pop-up on update (plus I don't like the umbrella icon...). Either one would be a very good choice, though.

AVG by far.