If you would have to buy an antivirus software in that moment, which would you choose? Interesant question
If I had a newer and more powerful computer - Kaspersky... no question for it's powerful unpacking engine. KAV would be my first choice overall. If I had a newer and more powerful computer and was a computer newbie - NAV 2004 or McAfee 8 for their ease of use. Since I have an older computer, I would choose F-Prot for Windows or Nod32. I chose Nod32 for it's excellent ITW results, automatic updates and more. If I was broke, I would go with AVG free. If I wanted an antivirus and firewall combined, I would go with McAfee 7 for it's ease of use and excellent test results. ... lots of "ifs."
I have used almost all the available av's at on time or another and At the present time I am useing panda platinum 7.0 . If I wasn't useing this one it would have to be mcafee 7.0. I don't like the interface on mcafee 8. check the link for very inexpensive mcafee7.0 and 8.0 http://www.softwareoutlet.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=UTI-001
Once I buy a mainframe, it's Kaspersky Anti-Virus all the way, baby. Till then, PC-cillin is the one for me. Everyone says that NOD32 is just oh-so-fast, but it caused serious lag on my system every time I launched a runtime-packed file. PC-cillin is much less CPU intensive as far as I'm concerned. You also have to be aware that some AV utilities won't show CPU usage primarily in their own processes, but rather in the "System" process. This is because of how they make use of filter drivers to do the scanning. Fire up Sysinternals Process Explorer, double click the "System" entry, click the Threads tab on the "System:[PID] Properties" dialog, then sort on the CPU column, descending. Look at the "Start Address" of the thread eating the most CPU time; it will name the driver which is using the CPU on that thread. You may be surprised.
If I have a newer machine then I would buy the king of overall detection and unpacking engine " Kaspersky Anti-Virus ( maybe KAV 5 ) ". But for my current machine I would buy Avast Pro or BitDefender standard edition.