Building an Energy-Efficient Dual-Core Box, Relatively Cheap

I've been remiss with my goal last year to post my recommended "monthly" build. So to tie it all up, I decided to make a wish list of sorts. This is how I would spec a compromise between an energy-efficient set-up and a comparably powerful machine. The considerations were an energy-efficient processor from AMD, a single hard-drive that had room for growth and a small enough footprint that would make it ideal for a regular-sized office desk.

The AMD Athlon BE line of processors have a TDP of 45 Watts, one of the lowest in today's bunch of mainstream processors. Adding a single large hard drive saves a few watts, compared to adding more hard drives later on. Using a SATA-300 drive will also make the set-up run faster. A small case is largely aesthetic, but it does make for a better office desk at home. Another consideration was a fairly recent motherboard (from a reputable manufacturer) that would make your set-up upgradeable for the foreseeable future. The board I chose also has onboard graphics (based on the latest AMD 780G chipset) that's powerful enough for casual gaming and hi-definition movie playback, so you save on having to buy a graphics card.

Now, on to my list:

• Athlon X2 BE-2400 (2.3GHZ, 1MB, 65NM, 45W) - $111.31
• Asus M3A78-EMH HDMI Motherboard -$99.99
  
• Kingston ValueRam 2GB (800MHz, DDR2, Kit of 2) - $46.98
  
• Seagate Barracuda 500 GB SATA (16 MB cache, 7200 RPM) - $ 111.99
• LG 20x DVD±RW SuperMulti Write (SATA, Black) - $46.79
  
• Antec NSK1300 MicroATX Cube PC Case - $89.99
  

That comes to a grand total of $507.05. The set-up is fairly powerful that you can live with it for at least the next 3 years. It will be capable enough that you can run virtualized environments and run different operating systems all at once. Cost was another consideration and I tried as much as possible to balance cost with fairly recent technology to make it as upgradeable as possible. So, tell me what you think?