Ah the good old which CPU question. This should get some healthy debate going.
Dare I ask the AMD or Intel question, but to at least make it a little less personally. Which is best for a newbie and why? Is one easier for the install or ongoing running. Lets ignore costs or types for the moment.
I'm using an AMD 4600+ dual core CPU in my core with 2 MB of Ram. Seems to work just fine.
If the price wasn't much different between a dual and quad core, sure, I'd get the quad core cpu... why not!?
If your hybrid core isn't serving up media to a dozen media directors, a dual core is just fine. I think you'll probably find the biggest bottleneck is the speed of data transfer in your hard drives and network.