New Build Server from Spare Parts

Hi, I've been lurking here a while after looking at various RAID type solutions for my home network and I've decided that unRAID is the way I want to go.

As my current main PC is long in the tooth, I am upgrading it and using the spare parts from that PC, along with others I have to make my unRAID server.

I will be using the server to hold all my pictures, video and music and streaming them directly to my htpc and PC and via wi-fi (through a serviio plugin or mediabrowser 3) to my android phones and tablet.

I don't have any fixed budget (maybe up to £300) - I don't want to spend too much (most of my budget is on my new main PC), but I do want a quality build that will last a while and be the basis of a great system for some time to come.

My build so far will consist of the following spare parts:

Case - Fractal Design Define XL

http://www.fractal-design.com/?view=product&category=9∏=54e

CPU - AMD Phenom II X3 720BE

Motherboard - Gigabyte GA-MA790FXT-u5D

http://www.gigabyte.com/products/product-page.aspx?pid=3005#ov

RAM - 8Gb Mushkin silverline DDR3

PSU - Corsair TX850

GPU - AMD Radeon 5450

Cache drive - 60Gb Kingston SSD

Array Drives - 10 Assorted 2Tb and 1Tb HDDs, primarily 7200rpm Samsung F2 and the like. One will be a Warm Drive

The additional parts that I am looking to buy to complete my build:

Parity Drive - WD Red 2Tb HDD

http://www.scan.co.uk/products/2tb-wd-red-wd20efrx-red-sata-6gb-sec-64mb-cache-intellipower-rpm-8ms-ncq-oem-24x7-use

HDD Controller - Supermicro AOC-SAS2LP-MV8

http://www.scan.co.uk/products/supermicro-8-port-sas-sata-card-(aoc-sas2lp-mv8)

FW Cables - LSI00258 - LSI CBL-SFF8087-SATASB-10M 1m Mini-SAS (SFF-8087) to SATA

http://www.scan.co.uk/products/supermicro-8-port-sas-sata-card-(aoc-sas2lp-mv8)

I am anticipating that the Case will be pretty full when I start off, but I will look to add some HDD Caddy's if possible at least in the front 5.25" bays, until I reach about 20 drives by adding new HDD's. If anyone can recommend any that work with the case I would be obliged.

Thanks

Dave