Best Case for Build

Most cases are fairly generic with some sporting different features to others. For the size of your components, you'd probably be good looking at a coolermaster. Perhaps a CM 690 II, which is a mid-size case (still much larger than most commercially available pre-built designs though). Try getting one though with USB 3.0 (CM 690 II Advanced) for the newer cpu.
A lot of it comes down to preference though, I just think this case is common and known to be cheaper, yet high quality.

Fractal Design Arc Midi: http://ncix.com/products/?sku=58475

Cooler Master HAF XB: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Rosewill BLACKHAWK Gaming ATX Mid Tower $59.99 after $15.00 rebate card http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Case:COOLER MASTER Storm Enforcer SGC-1000-KWN1 Black SECC / ABS Plastic ATX Mid Tower Computer Case ATX PS2 / EPS 12V (optional ) Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Case:Thermaltake Level 10 Series Level 10 GTS Black SECC ATX Mid Tower Computer Case
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Case:Corsair Carbide Series 400R Graphite grey and black Steel / Plastic ATX Mid Tower Gaming Case

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

No need to get a hulking case with those parts - less is more.

Fractal Design Arc Mini
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

And if you haven't bought a GPU yet, definitely go for this one before the sale ends: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Thanks everyone for the cases.
With the GPU, my 6870's fan seized up, and I'm waiting for XFX to get back to me on a possible RMA, but of course It has to break on Thanksgiving in the US, so their support team is most likely out of office.

So this really comes down to more of a preference and price point kind of situation.

Would I be better off going with a metal case, or are the plastic ones build just as well?

All cases are metal - just the front is plastic on most.