Hi everyone, I've decided to bite the bullet and try assembling a gaming PC. Since I'm switching from a laptop, I'd be building the actual CPU but also looking for monitor, keyboard, etc, with a budget of around two grand. 

My goals are a reasonable degree of future-proofing, so a PSU/Monitor/Case that will last several builds, and CPU/GPU/RAM with upgradability, so that in a year or two I can drop another $1000 or so on it, get a significant bump in performance, and have the whole PC provide good gaming for the next 5 years or more. In particular I'd like to be able to install a second GPU in SLI sometime down the line. 

I've put together a possible build based from looking at logicalincrements.com, and pricespy.co.nz, trying to find components that are value for money but reasonably well-respected brands. The list is here: http://pricespy.co.nz/list.php?l=91239&view=m (apparently I am too new to post links).

My main questions are: are there any obvious dud or overpriced components? How can I figure out if the various parts are compatible with the mobo I have chosen? And finally, is there any significant difference in performance between the ATI 7950 and the Nvidia 670 to justify the extra dosh?