Building New Game System - Target is ~$1350

NOTE: This is not a double post. I am building 2 systems. One for my wife and one for myself. I have separated it into 2 posts, since my goals and desires are different for each system.


Approximate Purchase Date: e.g.: This week, before the weekend

Budget Range: $1,350 before shipping

System Usage from Most to Least Important: I will be using this for gaming. I want the ability to expand to be able to run 3 monitors for 2D widescreen gaming. I imagine a single GTX 670 may not handle this well, so I would like a chance to possible add another one in the future.

Are you buying a monitor: No


Parts to Upgrade: Mobo, CPU, RAM, GPU, Cooling fan(s), SDD, 6.0 SATA HDD, possible a new case, PSU

Do you need to buy OS: No

Preferred Website(s) for Parts: This build will all be from Newegg.com, since we have an account there

Parts Preferences: Intel CPU preferred, otherwise open to other brands

Overclocking: Maybe, but from what I have read, OCing what increase FPS dramatically for World of Warcraft (which is about all that will be played on this build)

SLI or Crossfire: No

Your Monitor Resolution: 1680 x 1050 (one screen); 5040 x 1050 (three screens)

Additional Comments: The primary use for this build will be to play World of Warcraft. I want to play it on three screens (2d widescreen gaming) if possible. If FPS falls below 70 @ 5040 x 1050 I will cut it down to 1 screen until I can afford to SLI a 2nd or 3rd GPU. I will also play some high end FPS games, or perhaps games like Anno 2070. Warcraft will not be the only entertainment I seek. It would be nice to play newer games at a decent FPS with high-max settings.

And Most Importantly, Why Are You Upgrading: My current computer is over 4 years old and is having difficulties running Warcraft at modest settings. I want a computer that will last for 2-4 years (with upgrades to vid card and maybe CPU in 2 years) to last for the entire Mists of Pandaria expansion. I also want to be able to play newer games like Ghost Recon at a decent FPS. Max settings isn't essential, but high settings at around 70 FPS is preferred.

I am open to any criticisms. Though I consider myself highly skilled in building a PC, I haven't done so for over 4 years which means my hardware knowledge is far behind what I need it to be for a decent build.


Current Build:


Mother Board

GIGABYTE GA-Z77X-UD5H LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard

http://www.newegg.com/Product/Product.aspx?Item=N82E16813128545


CPU

Intel Core i7-2600K Sandy Bridge 3.4GHz (3.8GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor Intel HD Graphics 3000 BX80623I72600K

http://www.newegg.com/Product/Product.aspx?Item=N82E16819115070


RAM

Mushkin Enhanced Blackline 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model 997046

http://www.newegg.com/Product/Product.aspx?Item=N82E16820226296


GPU

GIGABYTE GV-N670OC-2GD GeForce GTX 670 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready SLI Support Video Card

http://www.newegg.com/Product/Product.aspx?Item=N82E16814125423


CPU Cooling

COOLER MASTER Hyper 212 EVO RR-212E-20PK-R2 Continuous Direct Contact 120mm Sleeve CPU Cooler Compatible with latest Intel 2011/1366/1155 and AMD FM1/AM3+

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103099


SDD

Mushkin Enhanced Chronos Deluxe MX MKNSSDCR120GB-MX 2.5" 120GB SATA III MLC Internal Solid State Drive (SSD)

http://www.newegg.com/Product/Product.aspx?Item=N82E16820226318


HDD

Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

http://www.newegg.com/Product/Product.aspx?Item=N82E16822136533


PSU

Please see question #3 below; I am considering this one though:

CORSAIR Enthusiast Series TX750 V2 750W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance Power Supply

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139021


Case

Please see question #4 below


Questions:

1.) I went with an i7-2600k Sandy in hopes of OC'ing one or 2 steps. Will this net me much of an FPS gain in Warcraft across 3 screens compared to an i5-2500k?

2.) Will I see much of a performance upgrade moving from 3.0 SATA to 6.0 SATA? We have plenty of 500 GB HDD's we could use and save some money. But, the 6.0 SATA's are not all that expensive. However, if I need to save money this could be one place to do it, -IF- there would not be that great / noticeable of a performance increase moving to the new 6.0

3.) My PSU is 550W. Can I keep that and make it work with this build, or should I buy a 750W if I plan on expanding to dual or triple SLI? Could i make the 550W work for now and upgrade when/if I move to dual+ SLI?

Current PSU is this:

Antec True Power Trio TP3-550 550W ATX12V SLI Certified CrossFire Ready Active PFC Power Supply with Three 12V Rails

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371002


4.) My case is an Antec 900 and I hate it. It gets dusty way too easy and is a pain to clean. However, it works fine, beyond aesthetics. Cooling also seems to be adequate. But if needed, I could cut costs and just deal with a dusty, nasty looking case. Would you suggest anything else? I love the Antec Sonata III http://www.newegg.com/Product/Product.aspx?Item=N82E16811129024 but it comes with a PSU I wouldn't need. I would like to consider moving to a case that was easy to clean, looks great but also cools well. However, to stay in budget and afford a more powerful system, this is also an upgrade I can wait for.

Here is my current case:

Antec Nine Hundred Black Steel ATX Mid Tower Computer Case with Upgraded USB 3.0

http://www.newegg.com/Product/Product.aspx?Item=N82E16811129021