The thing about AVs is the signature databases. Some have better Signature databases than others.
Norton and McAfee are good but you are chain your bank account to them.
AVG by Grisoft is OK but the Sig FDatabase is a little poor, Giving false Positives. The Flagging of RapidQ Basic as the Membrain Virus is a good example. (Membrain was written with RQ, but RQ is a legitimate program)
There are others.
Bitdefender Light and Antivir are perhaps better, Bit Defender Lite has a good database, it only missed one old Assembler coded virus in my library.
Bitdefender is also free.
Antivir is similar, not a pretty front end but OK for detection and deletion/repair
F-Prot, Loved by VXers but really like Norton and McAfee, money money money, unless you run in 16 bit DOS of course. (I use DOS foe assembler work so I use Fprot there, but refuse to be chained by the nose on their windows products)
Panda Antivirus is nice but getting it costs money and online form filling. (Which I do not trust).
A2 is nagware
If you are prepared to pay for an AV I would go for F-prot as this has the best signature databases. I believe this is the least costly pf the commercial AVs.
Personally I just prefer to write anti virus-viridae (Vxers use "Virii" when talikng plural for some reason) written in TASM, NASM or MASM (The latter two are OK on AMD 64 bit chips). I consider AVs using signature databases to be resuorce hogging and they chain you to the vendor for updates.
As for Sophos, Dont bother!
For No Cost Bitdefender and Antivir are the best.
For a Price F-prot is probably the best bargain.
shalom
Sophie.