Virus/Malware Protection?

Should i use AVG or Avast! i use AVG at the moment but i heard avast is pretty good

It's always a balance between performance, protection level, and compatibility.

The last one is really key as I have seen systems that will flat crash using one antivirus but work fine with another that has essentially all the same features.
At the end of the day I've finally just left it to personal preference.
MSE remains the lowest resource hog, but it's still behind some of the big names in detection.

If you keep windows completely up to date a lot of exploits will be patched which also helps security against viral and script attacks.

Have a look at this post & you can weigh the pros & cons:

What's the Best Anti-virus?

I had to revert back to Avast from MSE because MSE rendered my desktop useless for @ a minute after booting up the comp, due to a rootkit scan it was doing.
My wife had AVG in her laptop and it caused all kinds of problems with her game play so she used avast for years till it crapped out and now she uses MSE with no problems.
Norton is another story altogether but the bottom line IMO is stay away from it cause its not worth installing just to have hassles.
I'm looking for a antiviris to replace Avast but haven't come across one that I like yet so I have to continue using Avast.