I will go with the Avira only. It has created a big difference for me. I have never need to format my PC after installing this one. It has a huge difference than others. It use the same search engine in free edition as in the professional edition. So I used to prefer this for free users. If you can go with the paid ones than you may go with GData. It is German security suite totally working and also topped in the AV list in 2007 and 2009 (dunno about 2010). Also wanna say that only one thing is not important in the scenario of computer security. If you wanna go for the better protection than you should also try malewarebytes+comodo firewall with AV. These are also best in their category.