Google is worried that video will clog the Internet. AT&T is too. But VoIP Weekly has a quote from Deloitte:
"The unrelenting growth in Internet traffic in 2007 also may overwhelm the Internet’s backbone, Deloitte believes. "The terabit-cable pipes connecting continents will reach capacity and ISPs (Internet service providers) will not be prepared to pay for extra bandwidth because consumers will be unwilling to pay increased costs," Deloitte believes. Video is expected to represent a large part of the problem."
I'm going to have to think about how you prepare for that. On the WISPA list, the discussion about bandwidth limits arises often.