It doesn't actually make any difference how many viruses a certain AV product can recognize since the majority of the viruses do not exist anymore. There are also thousands of viruses that some people just made to "impress" anti-virus researchers. They actually let their code to spread, just sent it to AV houses.

What is important is that the AV product finds viruses that are in the wild. Check the wild list at http://www.virusbtn.com/WildLists/. Note that the wild list is very small compared to the whole list of viruses that products are supposed to find (and maybe clean).

- karnevil9