Steven, Planks, side planks... all good! And I've got two Power Wheels here at the gym... great peice, I agree and you can get pretty darn creative with 'em.
Well Melanie, I'm familiar with the rhetoric... i.e. marketing of them. I've seen them used. I feel for some purposes, increasing circulation for instance, it holds some value. But honestly, I'm not sold on the Power Plate for all the uses they purport it benefits. The idea, though implemented differently was part of training in the first 'spas' opened up in the 50's. You may have seen pictures... people standing with a band wrapped around them 'shaking' them. Granted, the Power Plate implements from the stance rather than around the waist but to me, I just don't see the effectiveness.
But to the greater point, and what I share with everyone... If you find something works for you, stay with it. It's about finding and working from your own choices. So keep on that Plate! :)