And ultimately it doesn't matter. What I mean is, it could be any one of these answers, depending on how you buy your media. And depending, too, on what kind of response you want. There is a distinct difference in how rich media affects the success of your media campaign. Chances are, if you're buying media on a CPM basis, you're looking primarily to brand yourself online.
Rich media is very engaging and works better and harder at branding than do static or HTML banners.
You'll get a lot more people clicking through it to get to your site, too. And if you sell on your site, the conversion rate versus number of impressions will likely improve. Here, the opposite of the above scenario may or may not be true. Here's where it doesn't matter what you use sort of. Branding doesn't matter a whit.