Nod32 is good also! Make sure if your on vista that you uninstall the older antivirus as two will cause some major problems and prob hurt your pc rather than help!
ESET Smart Security is from the makers of NOD 32. The software will include NOD 32 with other security features such as a firewall from the same makers. Not only for Vista, but for every operating system to uninstall the older anti-virus.