Snarkiness aside, you don't need an antivirus on your Mac. As long as you run as a non-admin user, enable a firmware password, and stay away from Adobe Flash, you are golden.
Wait.. an "admin user" on a Mac is basically just a sudoer that still needs to enter its password each time for elevated privileges, right ?
Since you do need to install stuff sometimes, I'm not sure what a power user who's careful about password prompts would gain from routinely running as a non-admin.
As someone who has used Macs since the 90s fairly carelessly I was quite impressed when a relative got a virus 3 weeks into his first Mac. All three of the above points were not followed.
Since you do need to install stuff sometimes, I'm not sure what a power user who's careful about password prompts would gain from routinely running as a non-admin.