thing is, i'm not sure you'd really want to get into clocking them, i'm not sure they'd really need it to be honest, as in there own ways there as fast as each other. either one of them matched with good ram and graphics card is gunna be a monster machine.
i'm going with the quad purely cos the only other option for me is a duel core 2.4, the 2.6 is 1333fsb as well.
what stepping is the 3ghz duel core? might be worth looking into..
graphics cards??.......