-spending too much on z97 board. a good h97 or b85 will do. z97 have a few more features, but mostly you are paying for better power and heat management for overclocking. you won't be overclocking so its a waste. your chip isnt meant to support it.
-750 ti won't hold up to new games well. even casual stuff. it is out of date at this point. budget, at minimum, an r7 370 or gtx 950 or save more money.
-WAY too much money for the case in your price bracket. you can get a case for $50 and put all that money into probably double the gaming performance.
-very low quality, poor choice for power supply. CX series are notorious for problems.