Owner and Group owner of files in my home In my Linux installations (Ubuntu and Debian), under the home of my user I only have files whose owner is my user and group owner is my primary group.

In my OSX 10.8.5, under the home of my user (username enzotib, primary group staff), I also have files whose owner or group owner (or both) is different. This is the situation:

Number of files   Owner   Group owner
      280        enzotib     admin
       29        root        wheel
       10        root        staff


Is that normal?
Can I (or should I) change something with chmod?
This is normal, to some extent. It really depends on what you have in your home directory. My home directory contains root user files from applications that require system-wide privileges for updating, such as Adobe Air and Parallels Desktop. Under normal circumstances there's no need to change groups or owners of these files.

If you're worried about the groups and users of OSX's own files in your home dir, run Disk Utility and repair permissions. This will fix the groups/users of OSX's own files, including the ones in your home dir.