Stock PS brushes work nicely for me. I've slowly become aware over the past couple of years that my method has changed. Beforehand I used to use different layer modes, different brushes, filters etc to kind of... I guess cheat my way to achieving a nice look.
Now, I literally just brush on what I want to be there, using this method I could create a chop from scratch on one layer. You find you have much more freedom this way, and it's really relaxing to just slap some colour on and build it up.
Because of this, I don't use brushes to create effects, I just use the stock brushes to well... paint I guess.