I agree with Freezingpictures... Sure, iPods are fantastic prizes, but I wouldn't use an iPod as much as I would a new lens or some lighting equipment! (In fact, I'd have to make sure that one of my daughters (ages 23 and 17) didn't sneak off with the iPod!

)
I don't shoot with a Canon nor a Nikon, myself. I am actually a Pentax person (unless I win the annual StockXpert contest, then I may just have to switch!

). I think a gift certificate to B&H, Adorama, or some other reputable online photography supply shop would be a great alternative prize for us photographers!
Btw, Steve-oh, I just joined StockXpert about a month ago, I am so glad I did! My sales there have been really encouraging so far (much better than any of the other non-subscription sites to which I contribute), uploading is easy, and the review times are the fastest I've seen anywhere!

Great job you all are doing there!