An antivirus that wasnt mentioned is
NOD32
NOD32's detection efficiency combined with 2-50 times faster hard disk scanning rate earned the product many international prestigious awards. NOD32 is the world leader of the Virus Bulletin 100% Awards having won more awards (23) than any competing product. Since its first submission for testing in May 1998, NOD32 was the only tested product that has never missed a single In the Wild virus. NOD32 has been selected as the "Antivirus program of 2001" by Australian PC User magazine, "Best Buy, Best Performance, Best Value" by the independent UK Consumer's Association.
Although it is not a free version, it is well worth your pennies