buy the OEM version but buy a non stock cooling like a zalman or arctic cooler. your old pentium d HSF i dont think would handle a C2D's heat well enough
Haha, you're funny. If the Pentium D's heatsink could handle the Pentium D's heat, it can easily handle a Core 2 Duo. The Core Microarchitecture is VERY cool compared to the Netburst architecture.