unless, as Mark alrewady said, if you want to capture your VHS tapes and stuff. Then you'll need an analogue to digital converter, otherwise known as a capture card.

For capturing stuff shot from your camera a firewire port and lead are all you need.

not likely as a noob you'll be playing with HD. More likely HDV but you won't NEED four cores for that although it would be handy. For example , I edit HDV on a single core 3GHz P4 and can scruib and edit in real time on it.

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I'm not young enough to know everything!