Setting environment variables on OS X

Question

What is the proper way to modify environment variables like PATH in OS X?

I\'ve looked on Google a little bit and found three different files to edit:

Answer 1

One thing to note in addition to the approaches suggested is that, in OS X 10.5 (Leopard) at least, the variables set in launchd.conf will be merged with the settings made in .profile. I suppose this is likely to be valid for the settings in ~/.MacOSX/environment.plist too, but I haven't verified.