The Raspberry Pi might be the most popular single board computer out there for Linux projects, but it's certainly not your only option. The folks over at LinuxGizmos put together a list of 40 boards that can run Linux to help you pick the right one for your projects.
LinuxGizmos' post digs through a lot of options for single board computers that can run Linux, from the Arduino TRE to the ZEDBoard. They talk about the specifics of each board, including its memory and processor, and then break down what each board can do. If you're working on a DIY project and want to take a look at all your options, LinuxGizmos' post is a great place to start.
Ringing in 2015 with 40 Linux-friendly hacker SBCs [LinuxGizmos]