I'm looking to buy a brand new system with AMD Athlon 64 processor.

Should I get the 754 or 939 pin model? I see that the 939pin mobo's also
support the FX version of the Athlon 64 chip. But are there any performance
difference(s) between the two?

Is there any reason that I might want to go for the 754? I see that both
types are priced about the same.

Thanks for your replies.