I finally decided to go with a ASRock Q1900 which has the Intel j1900 processor built in. Its a 4 core Celeron CPU and uses a low 10 watts of power. I had a slight issue getting Ubuntu 12.04 to place nice with the Realtek RTL8111GR NIC, but after rolling back the driver to version 8168, it has been running well.
In regard to performance, it scales well. It's not going to handle hundreds of concurrent users, but neither would my pipe. It serves up a few moderately busy WordPress installs as well as XenForo.... and then a few other virtual hosts, but nothing crazy.
The SSD and 8GB of Ram play a huge role in caching most the requested data, which eliminates a lot of strain on the CPU.
Overall, it will handle our needs just fine and has cut our power requirements by almost 8 fold. If anyone needs a power efficient media center or web server, you might take a look at the j1900. The Bay Trail lineup of CPUs pack a punch and don't need a whole lot of power to do it.