The spec of your new PC looks ok, but I would go for a Mobo based on the Intel p35 chipset as they support the new 45nm CPU's. That board you have picked is an sli board and priced accordingly. Unless you want to use 2x graphic cards I wouldnt bother. Incidently ATI is releasing a new dual core graphic card in January which will almost certainly thump the 8800.

I recently built a similar spec system to yours:

I went for q6600 (no brainer)
2 GB 800mhz Ram
Gigabyte P35 mobo went for this as it supports 45nm and has 8 sata 2 ports.