I think you just wasted some money unless of course you are running Windows Server. Even if you are trying to future proof; guess what; by that time, the price of the RAM will probably have fallen.
As for the 64 X2 4400+ processor, it is a great choice.
But I do have to ask. If you have that kind of money for RAM, why not have gotten a 64 X@ 4800+ or F60 processor? Oh wait, you meant the processor plus RAM was $1000.00. Oh well, after you put the RAM in, do a test to see if whatever version of windows you are running is "really" using all 4 GBs.