You're over building for 1080p gaming. Unless you're going to upgrade to a 1440p monitor, you can easily run games on max with a GTX 670 or 7870. That much ram is overkill. IMO the sabertooth is not really worth the extra money and you need to get ssd as a primary drive. It will be the single biggest improvement you can make.
If you want decent advice, reddit has an active community to rate your build.