Why does "not having root access" == security? I think people's personal files and information is FAR more important to be secured then some apps in \Program Files, and you don't need root access to manipulate the user's home directory, where they store most of their sensistive information, nor to open sockets, or access the keyboard and mouse.
You people suck at teh hax0r if you think UAC or root/user separation makes much a difference. As long as people have computers which can execute "software", there will be successful viruses written for them.
Because those types of issues can be removed. A rooted system is a reinstall.