What would be your ideal COMSOL workstation?

Hello all,

I am in the process of building my own COMSOL workstation, and am looking for advice. If you were building your own computer from scratch, what parts would you be sure to get (besides a supercomputer, of course)?

COMSOL's list of system requirements is pretty basic -- 1 GB of memory, 1-4 GB of hard disk space. I'd like to run 3D simulations with multiple physics, and also use parametric sweeps for optimization. Mainly, I'm looking to solve simulations as fast as I can.

Does anyone have any hardware recommendations?

Is there a noticeable difference between 64 bit and 32 bit performance?

Any speed differences between Windows (XP or 7) and Linux?

Optimal graphics card and memory size?

Number of cores?

I'm currently looking at an Intel quad-core processor and 8 GB of memory running 64-bit Windows 7. What do you all think?