If your systems at home are used for gaming and you transport files with external drives, here is an example of what to watch out for. We suggest that you refrain from mixing home and work systems. If your family members use you systems for popular games like Startcraft 2, you can get bitten.
First, the Starcraft 2 malware was discovered by Microsoft’s Malware Protection Center. The virus name is actually Harning, a virus discovered since 2006, which has infected well over 140 thousand files just in August 2010. The most infected areas with this virus are: US, UK, Brazil and Netherlands.
http://www.softsailor.com/news/43172-warning-a-starcraft-2-malware-virus-is-on-the-loose.html