You didn't say anything about HD video.
All depends on how H.264 tests out ... right now testing shows the need for high bandwidth (fastest FSBs) on the PowerPC.
Even the iMac G5 (and the PowerMac SP) with the FSB running at one-third speed suffers at the top resolutions.
Right now G5s with the half speed FSB have the edge.
If and when a dual core shows, it will all depend on how the threads are managed.