Alain is correct: Google needs to add video to the Google Talk client!
...and the Google Talk widget. I work in a U.S. government office, where Gmail's chat feature is disabled. Google Talk can be installed (indirectly; wink, wink!) but it can't support video.
I've read the two white papers from the company that developed the video technology. It's truly amazing stuff, going beyond Apple iChat's H.264 by intelligently dropping down in quality (S/N ratio), frame rate, and image dimensions when bandwidth is scarce, so as to prevent the image from freezing up.
By remaining silent on plans to add video to Google Talk, Google may be signaling an agressive move to "inspire" users of competing email systems into Gmail and, thereby, into the Google ecosystem.
By the way, when you use video in gmail chat, you can't use it to connect to your AIM buddies. Nor can you hold a group video call: It's like Skype: You can have a 3-way call or video, but not both.