May I suggest an OC of a cheaper C2D.  Mine is a e6400 running at 3.2ghz with an AC 775 Pro.  It would save ya 200 bills.  Also, intels price cuts and new processors are coming out next week...so wait and see if something better comes along for ya.

Rest looks good.  May I suggest this site too http://www.aqua-mac.com.  He built a very fine G5 PC, check it out.