Dual Core is a hot topic at the moment, and from personal experience (my iMac Core Duo, and a MacBook Pro currently on its way) it works very well. It is not so much the power of the CPU as the difference it gives in responsiveness - I don't get any of the freezes or pauses that I used to get when using my iMac Intel Core Duo.

I'm no stranger to multi-CPU systems, my first home PC (as opposed to the work units I'd been provided with) was a dual CPU unit. And of course my Niagara cased T1000 and T2000 units take the multi-core model to the extreme.

With the advent of dual-core, you have to wonder whether there is a difference between dual-core and dual-CPU. Is one faster than the other? Dual-CPU theoretically have more bandwidth available to each CPU, but the dual-core model allows information to be shared more effectively between the two cores because there is less distance between the two cores.