In my experience, OO is a good thing when you are able to imagine the 'objects' in some real-life representation (like GUI elements which are generally represented as 3 dimensional physical objects). Otherwise OO tends to be too abstract to help you, and already gets in your way.

This is very simple to prove: give a group of experienced coders the same 2 problems to solve: one taken from a real world object, and the other purely theoretic; both to realize in OO. This experiment would show that the real world object problem is solved in a similar manner, and the theoretic one in all different ways...

And yes, I use OO, but only with the libraries written in OO style, and never in my own code.