I have no experience with N800<->N800 video capability (maybe someone else can comment on that) but with Skype at least the video might take more horsepower than the N800 can muster.

For example, my notebook computer will cause the audio to seriously break up if I try to use Skype video. I have a processor usage widget and it gets pegged at 100% with the video on. Audio only Skype the processor stays in the 25-30% range if I remember correctly. My more powerful desktop has no problem at all with Skype video.

I'm just happy that Skype works as well as it does on the N800. With the good audio quality I can live without video.