How much watts for the PSU will this setup need?

Yea I'm with Rvilk on this his recommendations are good Corsair AX/HX/TX series are great I would stay clear of builders series as your system isn't a entry level machine. You may also be able to fine a TX750 cheap they were on sale as well which would leave you room to go SLi in the future if you decided to do so.

Just checked newegg, seems HX650 is at $79.99 after MIR
Seasonix X650 $89.99

So one of those would do great.

steals at the price the both are 80 plus gold which is something hard to find in that price range.

Well that 670 need 180W on peak w/o oc.

add 95W cpu ,15W hdd , 16W ram , 25W dvd

=331W +180W (SLI)

=511W add some oc = 550 W

So this will do the job

http://us.ncix.com/products/?sku=59616&vpn=P1650SNLB9&m...

And it can pull more than 650 W and its made by seasonic.

Good Luck !

You know what bothers me though about these 600 watt power supplies is that they only come with normally 2 6+2 12V power adapters where you have the 750 watt that supplies 4 connections. And just because you only need a certain amount of power you are assuming that 100 percent of the time it will only use that amount.

Yup just got done searching for that power supply you linked on here. And it only comes with 2 pci-e power adapters. I refuse to use some stupid adapter for sli if that was a route someone went.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
and then OH MAN magic 4 pci-e power adapters.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Even though 500 - 650 watts is enough, I'm just going to go with this:

http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

It's all ways better to have a little more just in case, or to have more then you need.

Best answer selected by storm slider.

That's right Storm great way to look at it headroom is a lovely thing to have.