Diablo 3 + W7 will be fine,but the "some applications" depend(on their size of course).
What motherboard do you want to get ?(maybe there are cheaper options)
haven't decided. cant really take side on p67 h67 and z68. sure z68 is superior, but do i need them for gaming/entertainment wise?
budget for MoBo is around $100~150. probably hardest choice i will make after ssd.
from what i've read so far, p67 and z68 is about the same in performance wise, just more features that doesnt help,(ivy compatibility except)