I use a stofen if I have no where to bounce off of or if i'm really lazy. Otherwise I use the built-in white card and a flag to hide the flash so I don't blind everyone. Much like Neil vN does here :
http://neilvn.com/tangents/2009/11/2...-foamie-thing/
I actually read his blog extensively when I first bought my speedlight. Now I refer to it from time to time to get ideas, but I think it has a great practical tutorial on on-camera flash.
[EDIT]: I just read "outdoors", and it's usually my stofen. If it's for fill light I sometimes just go bare.