@ Tension
The only way to watch a YouTube video properly on my iMacG4 @ 800Mhz is to let the whole thing download and then watch it, if you try to watch it online/live it's nothing more than a slide show (although the audio plays fine either way). I did at first think this was down to my broadband speed, as you can watch DVDs/Videos no problems offline, but this proved not to be the case as the iMacG5 @2.1Ghz I just got plays video online without problems at the same broadband speed.
I think myself it could be mainly down to MAC OS X being so processor intensive...

I assume this thing called OWB is something to do with MorphOs and not MAC OS X ?