OK, so barring anything wacky happening at MacWorld, I'm planning on buying a refurb Core Duo Macbook. I was originally going to buy a Mini, but I can sell my Powerbook Onyx for more than the price difference between the Mini & the MB, so I might as well get the lappy. My big question is: is it a mistake to go with the Core Duo when the Core 2 Duo is available? I checked out some reviews online and it seems like the C2D is up to 15% faster. I understand the math of 15%, but what I'm wondering is how much of that translates to real world. TIA.