BSOD after new PC build - driving me crazy!

Hi,
This BSOD is really twisting my melon! I built a new pc about 4 weeks ago now and it hasn't been stable since.

Asus P5B-E (and now P5W DH)
2x 1GB Elpida DDR2 RAM
Asus x1650 graphics 512MB (now powercolor x1950 256MB)
2x WD2500YS AHCI mode

I have tried clean installs of winxpsp2 and vista. I've swapped motherboards and graphics cards too. Interesting to note that the problem went away for about a week after i swapped out the graphics card, so i thought it might have been dodgy. But now the problem is back with avengence!

I will attach a couple of WinDBG analysis files. Let me know if anyone needs anything else?