do yourself a favor and take the pressure off by not setting a "must order by" date. if you rush to pick things out you can and will make mistakes. you can learn this the hard way or you can take the advice now and mull things over for a week while doing more research.
CPU: Intel Core i7-3770K Quad Core Processor Ivy Bridge 3.5GHz
-you can get away with an i5. in most cases this is what is recommended for budget gaming rigs. an i7 may improve performance in some programs or some high end games but it looks like you will not need this power and are on low budget. also if you dont plan on overclocking do not buy a cpu suffixed with K since you wouldnt need it unlocked (for overclocking).
GPU: EVGA GeForce GTX 660 Ti Superclocked+ NVIDIA Graphics Card with Backplate - 3GB
-i dont know about shogun2's requirements but benchmarks show this card can handle crysis warhead at 1920x1200 at maximum graphics while maintaining 38fps. i am guessing that shogun2 and similar games are much less demanding so you should be able to get more than enough performance out of the card for your tasks. for your own benefit try to find some gpu charts which list some lower end games and compare the results. you want at least 60fps. i always buy evga gfx cards myself.
Motherboard: Asus P8Z77-V LX Intel Z77 Socket 1155
-i am a fan of asus however this motherboard is only rated 3 of 5 stars on newegg. perhaps take a look at other asus models or products from evga, gigabyte, msi or maybe asrock. get one with good onboard sound and you can get rid of your soundcard.
RAM: Corsair Memory Vengeance Racing Red 16GB DDR3 1600MHz Dual Channel
-there is a deal going on for mushkin memory where you can get 2x8gb sticks of ddr3 1866 for the same price as most 1600 sticks. personally i would jump at this but your choice. corsair 1600, 16gb would work.
Case: AeroCool X-Predator
-should work fine
Sound Card: Creative Sound Blaster Recon3D PCIe
-i do like soundblaster but unless you are an audiophile and have decent speakers or in the case of a badly designed onboard soundcard where there is significant noise added to the signal you can most of the time get away with a soundcard included on the motherboard. in case you did notice an issue you can buy a sound card later.
Power Supply: EVGA 120 SuperNova NEX 650W Full Modular Power Supply 80+ GOLD
-i do like evga but in this case i would suggest a corsair hx650 or a pc power and cooling 650w
SSD: Kingston 120GB SSD V300 SATA 3 2.5"
-see my note below on ssd drives as it has information you need to know.
Cooling: NZXT Respire T20
-in a large case with adequate cooling you dont need an aftermarket cpu cooler. since you arent going to be playing anything demanding this is doubly true. of course this is your choice. if you add artic silver thermal paste to a cooler instead of the crap that comes on it you can normally get a few extra degrees lower.
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about ssds:
-a ssd drive is not going to increase game performance.
-a ssd will speed up boot times, increase performance in some programs and support faster transfer and read speeds. windows will feel snappier.
-you only want to fill up a ssd to 80% capacity or performance will degrade and you shorten the lifespan of your drive.
-the 80% rule for a 128gb drive would be 102.4gb useable. after 30gb for the os this leaves only 72.4 available which will fill up really quick.
-as an only drive i would suggest at minimum a 256 or if you want to just use the ssd for boot only then get a regular 7200 drive for programs
-the only ssd brands i would trust are samsung 830, 830, 840pro or intel. they performed good for mtbf tests and the rest of the brands had rather lackluster performance where there were many cases of premature failure.
in short: you would be better off buying a 7200 normal hdd for gaming but if you do want a ssd for speed of other applications and to reduce booting speed then you would be better with either a small ssd and a secondary hdd for files or buying a larger ssd if not buying a secondary hdd.