What permissions should I set if I'm the only user?

Question

I'm the only user on a OS X machine and am wondering what the best practice is for setting permissions on my sensitive files. Specifically, are there reasons to prefer one of the following

-rw-------   1 MyName  staff   ... File1 
-rw-rw----   1 MyName  MyName  ... File2
-rw-rw----   1 MyName  admin   ... File3

or perhaps even — what seems the most natural to me — no group at all with

-rw-------   1 MyName  MyName  ... File4

On OS X (10.8.2), the "default" is

-rw-r--r--   1 MyName  staff   ... FileA

but, until I, perhaps mistakenly, "reset permissions", most of my files had

-rw-r-----   1 MyName  MyName  ... FileB 

so one reason I'm asking is that I'm wondering what the consequences of my "reset" are.

Answer 1

Since you're the only user, logic says you have nothing to worry about. Should a remote possibility exist that someone else should have a user on that system, just be careful what privileges you assign. In short, the defaults will work fine.

Answer 2

It really won't matter if you try to set permissions to MyName:MyName or MyName:staff; the bottom line is anyone with 'staff' access on your machine is going to effectively have sudo access as well (namely, anyone who is an administrator on the machine.)

I personally wouldn't lose any sleep over OSX permissions; a capable sysadmin with 20 minutes of physical access to your computer can fairly quickly and easily compromise any file that is not encrypted; a live Ubuntu CD/USB key means they can completely bypass any permissions you may have set. If you have genuinely sensitive files, I'd create a truecrypt partition to store them in.