Hi Paul
I think that cash prizes in USD is probably easier all round...arranging to get goods to folk is probably a little time consuming. It is very likely that people have already got what they want when it comes to Laptops, Blackberry and Apple products etc etc. I like the idea of adventure type products that you would not normally buy yourself, but these are usually restricted to the country form where you purchase the event which may make it rather difficult for the winners to take up.
All in all cash is probably the preferred option
Paul