Well after quite a lot of consideration I went ahead and ordered the parts for my new rig. They should be ariving in the new couple of days and then the building starts over the weekend.
In the end I bought:
Thermaltake Tsunami Black Case
OCZ Modstream 520w psu
AMD Athlon 65 3500+ cpu 90nm
DFI Lanparty UT NF4 Ultra-D
2x512MB Corsair 3200XL Pro
XFX 6800gt PCIe
74GB WD Raptor HD
LG GSA4163B DVD Burner
I'm planning on getting it all setup at stock first and then look at various modifications.
I thought long and hard about both an SLi rig and having a Raid array. In the end could not really justify it.
Looking at the list of games currently supported on SLi I would not be getting any benefit from it yet as I dont play any of them.
Fingers crossed everything goes ok.