Any good security for free?

Just built my pc and need some good free security programs

http://personalfirewall.comodo.com/

I've got Microsoft Security Essentials combined with a weekly Malwarebytes scan. Works great so far, no impact on performance and completely free. 

According to Tom's Hardware and many others, MSE blows.  I would suggest Avast or AVG over MSE.  Malwarebytes is great though.  I've saved many systems with that program.  Here's a link explaining why MSE is so bad...

http://www.tomshardware.com/news/Microsoft-Security-Essentials-AV-TEST-Malware-Certification-Bitdefender,19452.html

The above could very well be outdated, but it's recent enough to scare the hell outta me.  I'll just stick with Avast.  It's doing an excellent job.

The point of MSE is it is exceptionally lightweight with a decent detection rate, mix with malwarebytes and your system doesn't need to spare much resources for security.

http://www.youtube.com/watch?v=mp6ytxMgckg here is a video on the free security apps around (and you will see why mse is a piece of shit!)

so will the free version do well or should i get the premium one?

The free vershon is fine