I am running norton internet security as i have been for a few years. I would like to switch but don't dare to try uninstall norton again as last time i did this i couldnt install stuff and it kept having remnants in the registry so i gave up and stuck with norton.
apparently trend micro pc-cillin is a very good programme, it is light and has a good reputation , read the reviews on amazon as well.
ALSO PANDA antivirus is good.
ps norton doesnt seem to fail too much for me, online scans normally corroborate with norton results and dont find anything in addition