I wouldn't install the 1333mhzFSB C2D just yet....I don't believe the BIOS supports 1333mhz CPUs....I have the D945GCL (OEM/in the same family) and it will support up to 1066mhz FSB CPU's. ---BUT, I don't believe they'll support quad cores either. I'm currently using the E6700 C2D (O/C 11% @ 2.94GHZ) w/1066mhz FSB that went in without any problems at all. If you DO manage a quad core, I'd sure like to hear about it....so post a solution & decision when you make it & install one if you do. Being OEM, my board doesn't easily take the Intel BIOS....I use the OEM BIOS, so that could be a limiting factor....but doubt that.
Anyway, the C2D is a better pick than a Pentium as it has a better use of juice , stays cooler, and has additional microcode in comparison. Hope that helps you. Good luck!