As the MacDefender phishing installing malware becomes prevalent, folks are repeating security advice such as the following from MacFixit (of the CNet organization):
If your working account is an administrator account, you can convert it to a non-admin account very easily, and this will not change the way your system runs at all. All it will do is require administrative credentials to perform certain tasks that otherwise could have been done without supplying credentials. As a result, your system will notify you if a program is trying to modify some system resources that would otherwise be freely editable if you were running in an admin account. To convert your account to a standard one, go to the Accounts system preferences and create a new account that will be your new administrator account. Give it a name and a password, and ensure that it has administrator capabilities. When the new administrator account has been made, log out of your current account and into the new admin account, and go back to the Accounts system preferences. Click the lock and authenticate your new admin credentials. Now select your old account and uncheck the box for “Allow user to administer this computer.” Now log out of your new admin account and back into your old account, and you’re good to go: you should be safer from these types of malware threats.
Geeks should note that “normal users” can’t use sudo at the command line without hacking the Mac environment a bit. I have not seen this limitation mentioned. For some, this adds a “con” to removing admin authority to normal user account.