Mac users ought to become more security concious -- learn how to set up and use user accounts, security features on wireless routers etc. -- but I have yet to spend three days cleaning off malware from a Mac nor have I seen the email addresses of corporate officers stolen from a Mac via virus and used to spam the company's employees with porn.
I can't say this about PCs.
The vast majority of Secunia's "vulnerabilities" require physical access to the computer. Those that don't, with the notable exception or two, involve services that are TURNED OFF in the default OS X installation... but Apple patches them anyway.
Secunia finds out about most of these because APPLE tells them because they are, for the most part, open source. How many things has Microsoft quietly patched and never mentioned, because they are considered "trade secrets."
Several times, when Secunia released its latest FUD, I have analyzed their exagerated "security levels" and found their hysteria totally unwaranted.