Generally speaking, direct flash is best for outdoors. If you are in the shade, you may find you get better results with the in flash bounce card, but your basically just reducing the power of the light.
I just came back from Disney, and spent the entire trip with my 580 mounted to my camera. I shot on AE with the flash set at -2/3 compensation, as a guide.
Below are two before and after shots.
The first, no fill:
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Fill, ETTL, -2/3 FEC, AE mode, Direct Flash
The camera can usually do a fairly good job if you give it a chance to drive for the family snapshot stuff.