HackerBoards has a list of 81, yes 81, hacker friendly, open-spec SBC all running Linux - and you can vote for the ones you like the best. You might even win a free board. It is worth a look just to see how many of them you already know!
Voting ends on June 17th
Ground rules for inclusion in the survey
Our definition of an open-spec, community backed hacker SBC is fairly loose. The boards must ship with extensive specs, as well as schematics for at least the carrier portion of sandwich-style boards. Additionally, they need to offer open source Linux or Android distributions for download. In the case of recently introduced SBCs, we allow a bit of a grace period to post the above resources in a timely manner, although we recognize there’s a growing problem of projects that are tardy in posting schematics, or more importantly for most users, optimized firmware.
The boards must also offer at least some community and technical support for individual developers. If we were voting ourselves, we’d give extra credit to projects with forums, tutorials, and other resources for sharing tips and designs based on the SBCs. Ideally, there would be explicit open source licensing for creating derivative hardware, although this is not required.
Full list and vote at: Hackerboards