Virus software...a must.
I have been mailed fourteen separate copies of the "W32/Sobig.F" virus just since this morning. I typically get at least one virus load a day on average.
If you do not have a really good anti-virus package on your system, you are risking your digital life with every keystroke.
I have had a lot of success with Norton, and my internet provider has filters of his own, too.
