Is an anti-virus even the right approach, especially for an experienced user? Wouldn't some sort of permissions management (maybe like SELinux or AppArmor) coupled with a firewall be just as secure? Getting the majority of your software from a repository (e.g. with yum or apt-get) also seems like it would help significantly.

I'm not a security expert, but it seems like you can have a perfectly secure computer without an anti-virus.