Class::Accessor is "popular" -- meaning that it's in the Phalanx list. Can't go wrong there.

The latest "new" thing, is inside-out objects, which provide an easy route to strong encapsulation. See xdg's scratchpad for several links to posts about them. I wrote Class::InsideOut to make it easy to use them and you might want to give it a try. For a more advanced take, there's Object::InsideOut. (However, I don't recommend Class::Std until some bugs and limitations are addressed.)

I'm sure others will suggest their favorites, too.