It's a good PC, but what types of mulit tasking do you do. You might be spending unnecessary money on that and the electricity bill.
You can watch TV and dl files on a dual core easily, so yeah if you do intensive multi-tasking then I'd recommend that, but if not avoid that. Be great if you can list what you do and what you multitask. (Keep in mind that pc would be great for working
casually with photo, movie editing etc.)
I'm probably not an intensive multi tasker. However, I do want to have quad core as a way of future proofing it (my understanding is that a lot more apps released in future will make more use of quad core).
I probably will play around with my own photo collection, do some word processing, browsing, watching tv. I may even do some movie editing.