Those permissions looks fine. 'wheel' is one of the older groups present in the *nix systems (by default, 'root' belongs to the 'wheel' group). It was originally used for specifying which users could 'su' to 'root'. On Mac OS X systems, most of the POSIX directories (/usr,/bin,/sbin,...) are typically owned by root:wheel and most of Apple's directories are owned by root:staff or root:admin. One thing to remember on most modern systems you are not the only user on the system; the only human user, maybe, but most of the system services run under alternate users/groups for security purposes.