I agree that putting methods into UNIVERSAL is a bad idea. However, there isn't anything wrong with having a base class for like objects. MyApp::Base::User for differnet types of users, etc. You get the idea.

Personally, I find it very rare that I have any methods that I want to provide for all objects in an application that can't be provided without the need for such a generate base class. For example, if I wanted to toString() an object I would just use Data::Dumper on the object itself.