It is no secret that there have been quite a few viruses floating around lately. It seems that they just get better and better. The virus software cannot stay up to speed with this stuff because it is literally impossible.
The best case scenario would be to secure against the methods that viruses use to enter your environment, but that is not going to happen. Even if it did, hackers would figure a new way in.
So, we have no option but to be reactionary. We react to new viruses that make it into our environments by running scans with the new DAT files and trying to clean things up.
The site that I have found that has the fastest information and DAT updates is the Trend Micro site:
The beauty of it is that they give you a free tool called "HouseCall" which will load a scan on your PC over the web that will use the same definitions that their regular products do.
If you know of any other sites like this one, drop me a line and let me know.