How to change all instances of "User" to "Agent" in 6.5.17 CE?

Hey guys - 

Since I am in insurance I would like to change all instances of the word "User", including the module to "Agent".  

Am I asking for trouble with this?  

What's the easiest way to do it? I have seen these types of posts.  But since they are a few years old thought I would at least ping the community.  

http://forums.sugarcrm.com/f6/how-rename-bugs-module-44230/

I appreciate the responses. 
Dale