I'll claim the best low cost video-conferencing solution on the market today is iChat.
It's OS X only of course. On the Windows side, this review lists about 16 iChat wannabes. It's just a list though, it doesn't tell you which are any good and which are on life support. I suspect all but Skype will be gone in a year or so.
The real message is that affordable video conferencing may finally escape from the icky home porn and the annoying 'young-geek-seeking-mate' industries.
Now if any of the competitors can provide an iChat like experience (esp. as with the original iSight firewire), we might get to save some gas money. I have a hunch we'll need either USB 3 (I miss firewire) or on-camera MPEG-4 like compression to really get where we need to go.