Need hardware help

in advanced, i'm sorry if this isn't the exact area i'm supposed to post this in, but, i just made an account for this post.
well, i need help with a new system that i'm trying to build, here's what i have so far.

MOTHERBOARD: ASUS Sabertooth X79 LGA 2011 Intel X79 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
CPU: Intel Core i7-3820 Quad-Core Processor 3.6 GHz 10 MB Cache LGA 2011 - BX80619I73820
GRAPHICS: EVGA GeForce GTX 660 SUPERCLOCKED 2048MB GDDR5 DVI HDMI DP Graphics Card 02G-P4-2662-KR
RAM: Corsair Vengeance Blue 16 GB DDR3 SDRAM Dual Channel Memory Kit CMZ16GX3M4A1600C9B
HARD DRIVE: Seagate Barracuda 7200 1 TB 7200RPM SATA 6 Gb/s NCQ 64MB Cache 3.5-Inch Internal Bare Drive ST1000DM003
OPITCAL DRIVE: Asus 24xDVD-RW Serial ATA Internal OEM Drive DRW-24B1ST (Black
WIFI CARD: ASUS(PCE-N15) maximum performance Wireless-N Network Adapter ( 300Mbps Transmit / 300Mbps Receive) with PCI-E interface, Include Full . Height and Low Profile bracket, WPS button Support
COOLING: Corsair Hydro Series H80 High Performance Liquid CPU Cooler (CWCH80)
CASE: Nzxt Technologies Phantom with Green Trim (Green LED) Enthusiast Full Tower Case - Phan-002Gr (Black)
POWER SUPPLY: ??????

so, onto the questions:

-would the motherboard and graphics card be compatible, I've googled the subject for a little while ad haven't been able to find much.
-should i get a sound card? or better yet, do i even need one?
-what is a power supply i should get, i know for the graphics card EVGA recommends at least 450 watts of powers, so what ever unit i need is fine.
- and lastly, is everything compatible?


I've been doing my research and things seem to be able to fit well together ( with the exception of not knowing about the graphics card and motherboard ) but i just want someone to double check it, if it's possible. as you may tell, this is my first time building a computer, and hardware specs are rather alien to me. And before someone asks, i'm looking for a gaming computer, not top of the line, but something that won't have too trouble running games such as skyrim, battlefield 3, and fallout 3. and i'm also not looking to run the games on the highest graphics setting, but i will if i can.