$3000 gaming PC build. Is it good?

You won't need x79 to run the 780ti. Or 1000W power supply. And you won't need 16gb ram

Try - http://www.tomshardware.com/reviews/system-builder-marathon-pc-overclocking,3771.html - 2 x 780's for $2400

or

CPU: Intel Core i7-4930K 3.4GHz 6-Core Processor ($576.99 @ SuperBiiz)
CPU Cooler: Noctua NH-D14 SE2011 CPU Cooler ($73.99 @ Amazon)
Motherboard: ASRock X79 Extreme6 ATX LGA2011 Motherboard ($214.99 @ Newegg)
Memory: G.Skill Ripjaws Z Series 16GB (2 x 8GB) DDR3-2133 Memory ($159.99 @ Newegg)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Drive ($154.99 @ Newegg)
Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive ($101.98 @ Amazon)
Video Card: Asus GeForce GTX 780 Ti 3GB DirectCU II Video Card ($669.99 @ Micro Center)
Case: Cooler Master HAF XM (Black) ATX Mid Tower Case ($69.99 @ Newegg)
Power Supply: SeaSonic M12II 650W 80+ Bronze Certified Semi-Modular ATX Power Supply ($166.82 @ Amazon)
Optical Drive: Lite-On IHBS312-98 Blu-Ray/DVD/CD Writer ($89.98 @ SuperBiiz)
Operating System: Microsoft Windows 8.1 Pro (OEM) (64-bit) ($129.98 @ OutletPC)
Wireless Network Adapter: Asus PCE-N53 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter ($35.99 @ Newegg)
Total: $2445.68


or

CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor ($339.98 @ SuperBiiz)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($24.99 @ Newegg)
Motherboard: ASRock Z97 EXTREME4 ATX LGA1150 Motherboard ($128.99 @ Newegg)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1600 Memory ($152.10 @ Newegg)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Drive ($154.99 @ Newegg)
Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive ($101.98 @ Amazon)
Video Card: Gigabyte Radeon R9 290 4GB WINDFORCE Video Card (2-Way CrossFire) ($389.99 @ NCIX US)
Video Card: Gigabyte Radeon R9 290 4GB WINDFORCE Video Card (2-Way CrossFire) ($389.99 @ NCIX US)
Case: Cooler Master HAF XM (Black) ATX Mid Tower Case ($69.99 @ Newegg)
Power Supply: Corsair Professional Gold 1200W 80+ Gold Certified Fully-Modular ATX Power Supply ($274.99 @ Best Buy)
Optical Drive: Lite-On IHBS312-98 Blu-Ray/DVD/CD Writer ($89.98 @ SuperBiiz)
Operating System: Microsoft Windows 8.1 Pro (OEM) (64-bit) ($129.98 @ OutletPC)
Monitor: Asus PA279Q 27.0" Monitor ($738.12 @ Amazon)
Wireless Network Adapter: Asus PCE-N53 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter ($35.99 @ Newegg)
Total: $3022.06

you should get 2 gtx 780ti

switch to maximus mobo it good for OC

No reason to get a 4930K for gaming - there's too much investment for not a lot of payoff in terms of performance gain. Try something like this:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($209.99 @ Amazon)
CPU Cooler: NZXT Kraken X61 106.1 CFM Liquid CPU Cooler ($136.99 @ SuperBiiz)
Motherboard: ASRock Z97 EXTREME6 ATX LGA1150 Motherboard ($149.99 @ Newegg)
Memory: G.Skill Ares Series 8GB (2 x 4GB) DDR3-2400 Memory ($86.99 @ Newegg)
Storage: Samsung 840 EVO 250GB 2.5" Solid State Drive ($149.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($52.92 @ Amazon)
Video Card: EVGA GeForce GTX 780 Ti 3GB Dual Classified ACX Video Card (2-Way SLI) ($659.00 @ Newegg)
Video Card: EVGA GeForce GTX 780 Ti 3GB Dual Classified ACX Video Card (2-Way SLI) ($659.00 @ Newegg)
Case: NZXT H440 (White/Black) ATX Mid Tower Case ($109.99 @ TigerDirect)
Power Supply: EVGA SuperNOVA 1000 P2 1000W 80+ Platinum Certified Fully-Modular ATX Power Supply ($186.99 @ SuperBiiz)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.99 @ NCIX US)
Total: $2491.84
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-08-23 04:10 EDT-0400

That gives you $700 to add whatever monitor, keyboard, mouse, etc you want.