Your logic is flawed. When building a gaming computer you want to put the most money towards GPU & CPU. The powersupply is overkill, and I doubt you need 1.5TB storage. The 550ti is not a good card.
You SHOULD spend more than 150$ for a GPU, save money on the storage and powersupply and put it towards that. A HD7850 would do good: http://www.newegg.com/Product/Product.aspx?Item=N82E16814161426
Swap the PSU for a XFX 650W http://www.newegg.com/Product/Product.aspx?Item=N82E16817207014
well everything looks alright, although i would definately choose a PSU with less wattage. 750W is too much for your needs in my opinion, so look for something maybe between 500W and 600W. Good brands are e.g. Antec, Seasonic, Corsair etc..
Yeah your PSU is too much, save some money on that, and you can get a smaller/slower HDD and it won't make much difference (to performance).
As Hannes said, all you really need is about 500 watts and a decent Thermaltake PSU at that wattage will be about $60 (here in Australia at least).
And if this is your first time building a PC you don't need the 3570k, just the regular 3570 will be cheaper, the only difference is that you can't overclock it, which I wouldn't recommend with your amount of experience anyway.
CPU: i5 3570. If you're not going to overclock, don't waste money on the unlocked K-series processors.
PSU: As many have stated, 750W is overkill. Honestly, your system won't use more than 300W. Get a decent 3-400W or even 500W if you're going to ad another GPU later on. I can highly recommend SeaSonic. If you're going for a GTX 660 (non-Ti) get a SeaSonic G-360W! It only has one 6-pin PCI-E connector, so you are very limited...
RAM: 2x 4GB, cool! Make sure they are CL9 and 1866MHz or above. Your motherboard will love you if you can find some 1.5V sticks (Logan explained why in the latest inbox video)
HDD: Oh God, Please NO! Don't go SeaGate. Western Digital is the way to go. See if you can scratch some money together and get a 120GB SSD.
Motherboard: If you're not going to overclock, you don't need a fixXxi & fancy motherboard. Find a "cheap" H77 or even Z77 board from one of the big manifactures (ASUS, Gigabyte, MSI, AsRock) with only the expansion slots, SATA ports and USB ports you need.
Optical? External USB optical drive my friend ;)
Otherwise, throw everything you can on the best GPU!
if you want to play newer games and have the money for a 3570, then you shouldnt go lower than a GTX 660ti or the AMD equivalent.. (I believe its the 7950, right guys?)
for games you wont notice any usefull benefit ram over 1600mhz..
Western Digital is the way to go.. (if you have you PC on most of the time, WD blacks is THE only ways to go..)
and lower the PSU.. I believe a 500 should even do the trick..