I use the simple 'slideshow to music' format. Though I haven't yet figured out how to get huge numbers of viewers (my view are all in the hundreds -- not thousands), I've had quite a few great sales from my YouTube viewers.
The number of views would organically increase, I'm sure, if I were more consistent and frequent with posting new videos. My goal is to post weekly, though I'm nowhere near that, yet. It's shameful, really, that I'm taking so little advantage of such a great, free -- and proven -- resource!
http://www.youtube.com/art166wj