What makes a good banner ad??

I thought i'd do a bit of research on this before i started designing, since i don't really know where to start.
Here's what i've gathered so far:

• Post banner ads on pages with related Web content -- the more related, the better.
• Advertise a particular product or service in your banner, rather than your site generally.
• If you do advertise a particular product or service, link the banner ad to that part of your Web site, rather than your home page.
• Put banner ads at the top of the page, rather than farther down.
• Use simple messages rather than complicated ones.
• Use animated ads rather than static ones.
• Your graphic content should pique visitor curiosity, without being too obscure.
• Keep banner ad size small. If the page takes too long to load, a lot of visitors will go on to another page
• A good banner advert should be visually appealing, attract interest, and be shown to an audience that is interested in what you have to offer.
• some inspiring ideas for placement of web banners: http://sixrevisions.com/design-showcase-inspiration/banner-ads-examples/