I agree, the San Diego is held on the faster processors whereas the Venice is seen on the slower ones. You don't see any FX processors with a Venice core but a San Diego.
Newcastle is out of the question. Winchester is even newer than that.
For your PSU, I would go with the OCZ 520w Modstream
for $105. If you're getting a 6800 GT, you will want extra power just to be safe. Spend the extra bucks for safety. I honestly just see no reason to save some $20 if you are at risk for stability and won't be able to get full potential out of your hardware (overclocking for example).
Antec is a reliable brand, but 430w just seems incredibly borderline for your system. You will be able to run things undoubtedly, but like caseyc said some while ago, under load things could be a different story.
I garauntee you that the 520w Modstream will run perfectly with no problems whatsoever (assuming the PSU is functioning properly). I run the 520w Powerstream which is an upgraded version to the Modstream, and it has saved my butt when I decided to do stupid things with boot.
You're basically going over budget to buy this more expensive modstream 520w to garauntee that you won't be buying your parts again and spending triple your budget.
Don't be that guy!