The nutritional yeast I ordered arrived yesterday.
It looks like fish food flakes (really!) and tastes like an aged cheddar or parmesan (minus the salt). I used a good amount (2 tablespoons or so) in our chicken burgers last night, just mixed it right in with the bread crumbs and seasonings. I also put some on my brussels sprouts.
I think I'm going to get a lot of use out of this, and I can't wait to see what other foods I can just slip it in, like I did with the burgers.
Here's more info, if you're intrigued: http://en.wikipedia.org/wiki/Nutritional_yeast