Pretty good choices. The i5-4590 has the best price-to-performance ratio of the i5's. The MSI motherboard (which is actually called the Z97 G45 Gaming, you have a typo) is used by a lot of gaming enthusiasts. The Hyper 212 EVO cooler is one of the most highly regarded air coolers for its low price and relatively high cooling performance for overclocking. R9 270 is a great choice for the price.
There are some problems with your build though:
1) The Motherboard Might Have Features You Don't Need
The Z97 is the best chipset there is to support your CPU, but some say that if you're not overclocking or popping in 2 graphics cards (I talk about linking graphics cards, aka SLI, in #5), then a Z97 board is not really needed. You could get along with an H97 chipset board. An H97 board is not any slower, it only supports less features than the Z97 and therefore, costs less. It's up to you though. The price difference between Z97 and H97-based boards is only like $15 in some cases.
2) You Need a More Powerful and Robust Power Supply.
450 W would be enough if this was a normal computer, but the video card (GPU) consumes a ton of power. The cheap models like the GTX 750 Ti uses only 60W, but a midrange like the GTX 760 uses 150W at full load, and a high-end like the GTX 780 can use up to 300W or more. Get a high quality power supply of at least 600 watts. Others can recommend you a specific model.
3) Get RAM that is as Dense as Possible
Keep your RAM in 8GB sticks. It saves a slot on your motherboard instead of putting in two 4GB ones, so if you upgrade, your potential memory capacity can be higher. It's generally not good to mix different capacity RAM sticks on the same board. It'll screw up system functions. Choose one size, one specific model, and stick to it the entire way.
4) The CPU Cooler is Generally Not Needed
You're not overclocking, so it's not needed. Matter of taste though. Keeping it to make your build prettier is a valid reason. The stock cooler is sort of ugly. And in general, it's better to keep your CPU as cool as possible if you want it to last longer. A larger cooler will help with that.
5) If You Have More Money, Spend it on a Better Video Card
Rule of thumb when upgrading your graphics card option is to first choose the fastest GPU you can afford (except maybe things like the GTX Titan, that thing is ludicrously priced). Still got more money? Great! Then get a second identical card. Don't first buy two slower cards and link them together for faster performance. SLI and Crossfire increase performance, but the communication between the two cards can never be perfectly in sync, so there are frame spikes.
I did find this deal though which might warrant breaking the rule.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125507
This GTX 660 comes with a $60 Watchdogs game voucher. The 660 is about as fast as the R9 270 you chose, but it costs only $180 with the game (it costs $220 normally without the game in other places), so you're effectively only paying $120 for it. Get two and SLI them for cheap!
I must say that getting a faster graphics card or getting two is a matter of personal preference. If you're satisfied with the results you get from a slower card, then it's okay not to get a faster, potentially much more expensive one.
That's all I have for now. Questions? Glad to answer them.
Facebook
Twitter
Instagram