Low end media rulez!
There's a great article today over at Jakob Nielsen's site: Low-End Media for User Empowerment.
The summary is that on web sites, low-end media (text and static images) is, on the whole, much more usable and useful than high-end media (swoopy animated graphics, complex Flash navigation models, video, 3-d models).
Nielsen lists some technical impediments to high-end media, like download time, searchability, and accessibility, but rightly points out that those limitations will pass with time.
The greater problem, as Nielsen points out, is the issue of user control. As soon as something starts spinning, or animating, or making noise unasked, the user has lost control. As soon as content is streamed to the user, instead of allowing them to read or skim at their own pace, the user has lost control. The more a site tends towards fancy swoopy interface models and away from "click this clearly labeled link to see that relevant information", the less sure the user is of what they're going to see, and the less control they have over what they see.
And the dai-ichiban number one main thing the user wants, as I've said elsewhere, is to maintain control over their experience.
There are, of course, exceptions to the rule. Showing video of the Berlin Wall falling, or Rodney King getting beaten, is much more affective than still photos could ever be. But in cases where video would be useful, showing a still or two from the video as a preview gives control back to the user: "This is what you're going to see. Will it be worth it to you?"
It's constantly amusing to me that so many of the bad decisions people make about what to do with their sites could be solved asking a question I learned in the first term of my design education: "Is the design weaker without it? If not, then take it away." Is someone's experience really enhanced by that spinning golden arrow? If not, a simpler solution will probably be better.