middigit - just why are you changing permissions? there are good reasons at times to change them, but generally, UNIX gets it right the first time.
I'm speaking from the experience of watching my spousal unit change permissions because "I want them to be mine!" Eventually, programs or the whole system are not working, and it's time to run Disk Utility again to correct them for her.
If you know what you are doing and why, yeah, change them in the "get info" box for individual files or apps.