Advice on building an energy efficient home server

I'm looking into building a server - I've done this many times before, however, I've never considered energy efficiency before.

The main purpose of this server will be for storage, streaming films and music, plus any other normal home server type stuff, so I want it to be budget but capable and will pay a bit more for energy efficiency.

I guess the first thing I need to look at is power supply, CPU and HDD (thinking striped SATA)... any recommendations or charts people can suggest for me to look at to help me buy the components I need.

MB+CPU => With your server needs the main thing will be a good disk solution so either the Intel Atom or AMD Zecate would fit the processing needs. The AMD E-350 is pretty impressive with its low power draw and good performance. The ASUS one below has 5 SATA III ports for your RAID, but you can add additional controllers if needed.
http://www.newegg.com/Product/Prod [...] -_-Product

HD - For drives, look at the Samsung F4 2TB or Hitachi 5K3000 2TB. They are both 5400RPM drives, but will deliver good performance and power efficiency.

PSU - With five drives and a few case fans, your power draw would most likely be under 200w. Get a quality power supply from Antec, Corsair, XFX or Seasonic with a minimum of an 80+ Bronze certification. You, after all, are interested in effecient power consumption...
Seasonic 300w => http://www.newegg.com/Product/Prod [...] -_-Product

You should be looking at a i3-2100 (65w) or i3-2100T (35w) and a H61 motherboard. Even the low power 2100T is 4x more powerful than the E350.

http://www.xbitlabs.com/articles/c [...] html#sect0

http://www.xbitlabs.com/articles/c [...] html#sect0

The Asrock H61 mobo I'm running was only $59.

I set out to build a low power "green" pc and wanted to keep my HD5850, I went this route but the 2100T looked a tad slow to me so I went for the 65w. For your needs the 35w would be more than enough to last you many years.