A P45 or P43 mobo would work pretty well.
PSU size calculator: http://www.extreme.outervision.com/psucalculatorlite.jsp
550W-600W would probably be a good size. Don't buy a cheap one.
People will tell you that the e8600 would be faster in current games. If I were the one buying, however, I would choose the quad for much greater future-resistance.