building a new desktop......details inside

[strikeraj]

Hi everyone
I would like to build a desktop to do the followings:
Engineering softwares - CATIA, Abaqus, MSC.Nastran/Patran, Ansys, Matlab, etc
Games - Battlefield series, TF2, Company of Heroes series, combat fighter games, modern or WW II FPS, etc

No/minimal O/C, chances of long time full load simulations (>8 hrs)
possible to turn off display card and use internal graphics when not gaming?

Here is my think on each component:
CPU - does not really matter if it is AMD or Intel, as long as it serves my purpose
Mobo - has to be REALLY stable, cause I dun want my simulation running to 99% and computer crashes
RAM - Same as CPU, 6GB or more will be good i think (do i need a 64bit OS to use all memories?)
Graphics - Gaming oriented, not much real time rendering work in what I do
HDD - if possible a rig running at raid 0, I have a home file server so I do not need a huge capacity on my desktop. Enough to hold all softwares and currently in use files. I am thinking 160GB or 320GB is good.
Optical drive - reads blu-ray and writes DVD... not very often though
Case and cooling system - I want something that is decently quiet and cool, and most importantly, minimal dust cleaning required... best if I only needs to change dust filters... should i go WC?
PSU - anything that is stable and efficient
monitor - looking at 22-24" LCD that can rotate 90 degree for viewing documents, preferably non-TN screens if budget allows
other peripherals - i have mouse, kb and speakers, so im good

Budget - $1500 including monitor (...and tax if possible)

I will be buying components off internet shops (NCIX, tigerdirect, neweggs) and local stores like canada computers (i am located in kitchener, ON)

Here I would like to thank all contributers to this thread in advance

[Kayen]

Graphics : Go for an ATI 4890.
HDD: If that's all you need, invest in an SSD , much faster, better read/write times.
Power supply: Go for a corsair / seasonic very high quality, quiet + stable.
Case: Lancool Dragonlord PC-K62, see review here on HWC, will fit the bill nicely.

[Sushi Warrior]

i7 for sure. You need lots of threads. I would invest in lots of cooling, some fans and a good heatsink as well as a good case. For HDD's I'd get a cheap SSD and store whatever you're working on at the time on it and a decent sized storage HDD (500GB). As far as graphics go get a GTX260 as it has better power consumption specs, although 4890's so seem to be coming on sale often.

EDIT: And Nvidia's CUDA technology seems like it would be good to have for someone doing what you're doing.