I like the 750k for gaming, it's a great budget cpu. I have never had a r7 250x, however, specs aren't bad on them for some entry games. What are you planning on playing? Why are you going with a micro atx board? I would just go standard atx, maybe pickup a few more features. The case looks fine, comes with 2 fans already I would say just get one more for the top for extra exhause and cooling and you would be good. If you are not planning on over locking you 750k, the stock cooler does great.
A great website for you to check out for compatibility is pcpartpicker, these guys here are great but sometimes it is a lot of work for them to check every part to make sure it goes together. That site chooses what is compatible when you choose one component and you build as you go. Good luck and have fun, hope this helped.
Drop the optical drive and start with 4GB RAM and use the extra money to get a much better video card. You can always add more RAM and a disc driver later when you get more money. I recommend going with a R7 260x or GTX750 at the very least, but a R7 265 or GTX750ti would be much better.
Also try to get a better motherboard. That motherboard is just terrible.
Thanks for your answers. I think I'll do what you said, CTurbo, when you said to drop the optical drive for later. I kinda want to keep the 8GB of ram though. And thanks, Prestomatic for telling me about the micro and standard motherboards. I don't know much about motherboards so I'll do some more research. I also used pcpartpicker to make this build. What do you guys think of this motherboard ASRock FM2A88X Extreme4+ ATX FM2+ Motherboard?
Adding RAM is quick and easy and could be done at anytime. 4GB is actually enough for 90% of all PC uses right now. The extra $30something you save on the RAM will go a long way towards a better video card.
I decided to downgrade to 4GB of Ram, saves me $40, and to also get rid of the optical drive for later. I'm thinking of getting this video card, MSI Radeon R7 260X 2GB Video Card for $145 (I live in Canada so the prices are usually different, and when I say different, I mean higher). The Radeon R7 265 2GB was about $180 in Canada.
Update: I just found the GTX 750 Ti 2GB for $150, so I'll probably get that.