CPU- Intel i7 4790K.
Intel's 4 core i7 is a little stronger than AMD's 8XXX/9XXX CPUs in games. Why i7 over i5? Hyperthreading. Does it matter right now? No. Will it matter in 2 years, when you still plan to have this PC? Probably. Already there are games out there that can take advantage of (but do not require to run well) more than 4 threads. The i7 may be $100 more than the i5, but I think it is worth while to future proof your system a little bit. Witchdoctor would be my strongest backer on the subject on these forums. Hopefully he will see this and post.
MOBO- ASRock Z97 Extreme6
Good power delivery area, excellent connectivity (TWO M.2 ports. One is ultra M.2) and a great feature set for the price. IMO you can't beat this board for the money. ASRock used to be a bargain bin board maker but they have come a long way and now deliver high quality and high value.
RAM- 2x4GB 2133Mhz Cas11 DDR3
Haswell scales well with faster RAM in games. People have reported gaining a couple of frames per second from going from 1333mhz to 2133mhz RAM. Is it a big difference? No. Quite tiny. But it's there. 2133 kits cost only peanuts more than 1600 kits these days if you shop around. Worth it IMO.
Cooler- Noctua NHD15
It'll fit on this board, due to the first expansion slot being a X1. Best performing air cooler out there. Others have steered you clear of AIO and I won't argue with them. The D15 is ugly, but it gets the job done.
GPU- Nvidia GTX 970
Gtx 780 performance for just over $300. Can't argue with that. Great value for the money and really sips power which will reduce your electric bill
Case- Personal preference
Pick a case that you like the look of, firstly. Look at the airflow it provides. Is it going to provide enough air flow for your overclocked CPU and (probably also overclocked) GPU(s)?
Are there dust filters on all the air intakes? Are they easy to clean? Does the case offer good cable management and routing options? Do you like the mounting system for the HDD/ODD bays? Are the HDD bays removable? Etc.
PSU-
Look at a Seasonic gold rated 600-650W for single 970 and 850W if you plan to add a second 970. Evga Supernova is also very good. If you want to save some $$, and are going single card, get a Corsair CX600. They are rock bottom cheap and pretty reliable.
Storage- Samsung EVO/WD Caviar Blue
I say pick up a 1TB Samsung 840 EVO and be done with it but that'll be outside your budget. Instead grab a 128GB EVO for your OS and important programs, and a 1TB WD Caviar blue for game installs and files.