If you are buying in the near future check out the sales that ncix run,
here is the link (in case you didn't notice the banner on the side of your pages/ or you have adblocker blocking them) you can usually get some better deals simply by clicking a different URL for the same part.
http://www.ncix.com/promo/promosale.php?webid=14days
I would recommend getting a ultima 90 heatsink + a Scythe F fan if you plan to OC.
For about the same money as the Xeon(via the sale) you can get a Q6600. It also comes with FREE shipping on the entire order....always nice bonus. It runs at 2.4ghz so thats the same as a mild OC on the Xeon. Plus not all boards play nice with Xeons. I have no first hand experience with OC'ing a xeon on this board so will not comment on its potential or even if it will work (proly would)
When I build systems I use Abit for "budget" ones and Gigabyte or Asus for everything else. For your price range the Gigabyte is a nice choice...as long as you can live with the Fisher Price color scheme.
Recently I had a bad experience with Patriot so I AM biased when it comes to them. I can say that for the same money you can get Mushkin HP2-6400 ram. Mushkin has always been my first choice as they OC very well AND have great customer service.
Another good choice in your price range is the Crucial Ballastix. While no one can guarantee that you will get Micron D9s w/ the Mushkin HP line you WILL get Micron D9s with Crucial. Crucial IS Micron and they OC amazingly well. To me either would be fine as you will most likely "hit the wall" becasue of your CPU long before you hit the upper end of either brand rams OC'ing potential.
You didn't mention what Power Supply you plan on using. To many people over look this when they are building and it comes back to bite them. Where you are planning on OC'ing I recoemend a GOOD one such as the Corsair 520 (if you are not into gaming and don't need a 8800) its on sale for 87 bucks! Or the Corsair 620 also on sale.
YMMV but that is my 2 cents worth.
AkG