New av-comparatives may 2009 for Retrospective/Proactive Test report is out now and it shows how Symantec's Norton performs..sadly it gets advance rating...
Here is the report link:
http://www.av-comparatives.org/comparativesreviews/main-tests
Norton Internet Security 2009 16.5.0.135 ; Windows Vista Ultimate SP2 x64 ; Intel Core 2 Quad @ 2.40 Ghz ; 8 GB RAM ; 500 GB SATA 2 HDD Western Digital