At first it looks like you have a budget build in mind, then you talk about 64 GB RAM, which could itself be more expensive than the entire system you noted, above.
Perhaps the pertinent question is this: What's your budget?
If you have a few thousand dollars to spend you could build a SIGNIFICANTLY better workstation than for one thousand dollars.
If you have ten thousand dollars to spend I doubt you could get a more powerful system on the planet than one of the new Dell Precision T5600 workstations.
My point is that everyone has a target price in mind, and for any given price you can only build so much system, which in turn will be useful for a certain amount of time before it becomes obsolete.
-Noel
