What PSU Should I Get With This Build?

The only critique I can make is to advise you not to buy an R9 380X as the Rx 480 will be on the market early July and will offer significantly higher performance for 200$.

As for the PSU, this one is a high quality full modular, and this is a high quality semi-modular.

EVGA,Corsair, Seasonic all have decent PSUs.
The PSU is the heart and life blood of your system and should not be underestimated.
You have chosen a decent build so choose a unit that is:
A: Gold or Platinum Certified.
B: Choose a Wattage that is slightly above your minimal requirement for future expansion.
Go here to help you decide: http://outervision.com/power-supply-calculator

Efficiency rating doesn't really matter as much as build quality, and no, higher efficiency rating doesn't mean better quality.

Always advise against power supply calculators as they give fairly inaccurate results.

Efficiency is all important and build quality WELL you get what you pay for, but shop around.
Let the OP decide IF the calculator helps him or not.

It's not really helpful to the OP to just criticize my post.

It's not about whether the calculator helps or not, it's about whether it gives accurate information, which no calculator I know of (this one included) does.

Efficiency isn't "all important", and with build quality no, you don't get what you pay for. For example the Corsair CX series are utter junk, but you can often find them more expensive than a Seasonic S12II which is a good PSU. Another example are the Corsair RM series. An RM850 (note: not RMx or RMi) doesn't have near as good build quality as an EVGA 850 G2 despite having the same efficiency rating and practically the same price.

It's not helpful to the OP when people give inaccurate information. I appreciate the many people helping others on this forum, including you, but I have to correct inaccurate information.

Oh here we go, Typical troll statements. Misinformation and your opinion is better than mine Blah Blah.
You can have the last say. If you need the browney points.

I have given no misinformation and have not stated that my opinion is better than yours (simply I am not expressing opinion). If wish to get an idea on the differences in PSU quality, you can always check the reviews from jonnyguru (or even other sites) and see what kind of build quality and performance (noise, ripple etc.) different PSUs offer and why build quality is not linear relative to price.

I am sorry if I have offended you, I did not intend for any of the above posts to be viewed as any form of personal attack.

For the facts and not merely conjecture.
Go here: http://blog.nzxt.com/2015/10/5-important-things-to-consider-when-choosing-a-power-supply/
And here: http://www.extremetech.com/extreme/143029-empowered-can-high-efficiency-power-supplies-cut-your-electricity-bill
And here; http://blog.usro.net/how-important-is-the-power-supply-in-your-pc-and-what-power-supply-to-buy/
And here: http://www.pcauthority.com.au/Feature/356985,how-to-choose-the-right-power-supply-for-your-pc.aspx

Wow, you guys really went off the rails here. I think the OP was just looking for a simple suggestion for a PSU (make and model) not a debate over efficiency or build quality.

That said I wouldn't mind putting in my two cents. First off all PSU calculators are making best guesses, some are better than others. I generally trust the Outervision PSU calculator. Most calculators are going to guess on the high side which for the most part is the best option. One thing to make sure of when looking at the power rating on a PSU is whether it can supply nearly 100% of it's full rating to the 12V supply. If it can't then skip that PSU entirely as the 3.3V and 5V supplies are much less important in the overall scheme of things. This is where going by a PSU calculator's "guess" can lead you astray. For instance lets say OuterVision's PSU calculator recommended a 550W supply. If you look strictly at the wattage and not the amperage recommendations for the individual supplies you could get burned. There are cheap PSU's out there that only supply 50 - 60 % of the total maximum wattage on the 12V supply while "technically" still able to deliver the rated power rating. Since most modern systems lean heavily on the 12V supply, these PSU's will fail or misbehave under load.

As for efficiency, this alone means nothing. There are plenty of garbage PSU's out there that are "Gold" rated. It takes a more in depth look at the internals of the PSU. There are some very good "Bronze" rated PSU's. That all said, if you look at a decent make (Seasonic, XFX, EVGA (some), etc), generally speaking the Gold models are going to be better quality than the Bronze models from the same maker. It's more due to economics. The manufacturer markets the Bronze supplies to a lower priced market segment than they do the Gold. So when a Bronze PSU costs less than a Gold PSU from the same manufacturer, you can bet the BOM on the Bronze PSU is less. If the BOM is less then it stands to reason that they had to cut cost somewhere. Whether it's the quality of the caps used or less advanced design, cheaper supervisory circuitry, cheaper protection components, etc. You can't say brand X's Gold is better than brand Y's Bronze based solely off of the efficiency rating because brand Y may have a higher overall standard for quality than brand X.

Generally you get what you pay for, though there are exceptions. There is a reason why Ultra PSU's are cheaper than Seasonic regardless of the efficiency rating. I don't mean to pick on Ultra, you could place a hundred other manufacturers names in for Ultra and it would still be accurate. You also can't always go by the past reputation of the manufacturer as is the case with Corsair. Back in the day, Corsair made some very good quality PSU's (TX and HX series), but more recently they've made a lot of junk (CX, RM, CS). To determine quality you really need to get reviews from respected, reputable sites like HardOCP, Tom's, and Johnny Guru.

Also another thing that should be mentioned, when I say manufacturer, I use that term loosely. Most "manufacturers" don't actually manufacture any of their PSU's, they outsource it to OEM's like Super Flower, Channel Well, Seasonic, HEC, etc. So a company like Corsair, EVGA, and XFX just slap their name on it, they don't design or build it. It should also be mentioned that not all models of say Corsair PSU's are made by the same OEM. For instance EVGA uses Super Flower for there SuperNova G2's while the 500B is made by HEC.

So determining quality is difficult as you can't use a brands past reputation, or efficiency rating. It's nearly impossible to look at a black box and say that its a good PSU. You can't even reliably use the OEM to determine quality as the OEM builds to price as requested by the "manufacturer", so one Super Flower build maybe better than another. Even if the design is same, component choice (particularly capacitors) affect both price and quality.