I really do think that something big will be going down. It could be an Intel based PowerPC solution or a x86 based system. Both will win for Apple in the long run.
As much as I love the idea of running OSX on my AMD 64 5000+ SLi system, I don't actually think it would feel right. Macs are meant to be different and special. Its been my dream to own a Mac since I first saw a G3 and should I be able to afford it I would run out and get one straight away, I find the little Apple badge to be the height of fashion and I really really want a Mac Mini. Its only the cost and the fact that my PC can do everything that I want plus gaming right now that puts me off.
I'm very much an expert with PCs and Windows yet I really do now consider recommending Macs, particularly Minis to 'the average buyer' that I know - i.e. student girls who don't really know much about computers. They can get a mac and be happy because they're so easy to use and more importantly, they look good.
Not a single PC based company has been able to create anything that even remotely looks as nice as any of the Macs (current imac excluded). Macs are special, Macs are fashionable. Macs are easy to use. Whatever happens, it should stay that way.