I converted from PC to Mac several years ago and have basically never looked back.

Some points to consider:

Photoshop CS3 is being written specifically to be compatable with the Dual core machines.

The biggest problems with the new intel chip stem more from a Mac users standpoint than a Windows user standpoint. Because the chip is new to Mac, most older Mac software has compatability problems. Apple has done some work in reducing this problem, but most of the older software that is compatable runs slower than it normally would (I assume that it's going through some sort of 'translation' process). Photoshop CS2 for Mac is no exception to this rule.

I'm really not that knowlegable on the Windows compatablity side of the Duocore, as Windows problems have not concerned me for quite awhile.

Internet security is going to be an issue with the DuoCore chips. Apple has never had to worry much about internet secuity, as most viruses were written for the Intel chips running Windows. Now that Apple has placed itself into that arena, I would want to speak with an Apple rep before buying the new machine.

That said, my next machine will be a dual core, though I think I'm still a ways off from that.

I would recommend talking to your local Apple Store/ Mac Store. They're going to be the most knowlegable people regarding your questions. Just keep in mind that theirs is a biased viewpoint. They are, after all, trying to sell you their product.

-Joe U.