Advice for a new workstation

[shtarkel]

Hi, I am building a new ArchiCAD and 3dMax workstation and I have some doubts of what would be the best machine for around $4500. Use multiprocessing or single but more powerful

case - Supermicro SC743TQ-865-SQ
MB - Supermicro X8DAI or GIGABYTE GA-X58A-UD9 for single xeon w3680 ?
CPU - one Xeon x5680 or two x5650 ?
RAM 12GB x1333 - G.skill , OCZ, Corsair, Crusial ?
GC- FX 3800
HDD- SAS 15k ? is it so important to have a super fast HDD

I am looking forward to read some advices...

[Laszlo Nagy]

I second Miguel's words.
My notebook became more than 2 years old this fall and became very slow and sluggish.
Programs in 32-bit Vista can not use the full 4 GB RAM.
I bought a 60 GB SSD drive and Windows 7 64-bit. It is an OCZ Vertex 2, which I highly recommend because both its read and write rate is like 270 MB/sec, yeees, megabytes per second.
I made the SSD drive my system partition for Window 7.
My computer feels very snappy and responsive now.
Just one example: Vista used to take about 2-3 minutes to boot.
Win7 with SSD takes about 40 seconds.
It really makes such a huge difference when all your system files are on an SSD partition and the system is loading them at the speed of RAM instead of the speed of a hard driver.
I will never have another computer with an HDD system partition again.
I think I will now be able to use this computer for 4 years instead of the 3 years originally planned.
The only thing I would want is 8 GB of RAM instead of the 4 GB max. possible.