First question: What's the most popular open standard board type used in open standards-based systems? Answer: the personal computer, both in desktop and laptop sizes. But if we narrow the question to "rugged, deployed and industrial systems," you'd primarily find PC/104 and its ilk, Computer-On-Module (COM), EPIC, and a bunch of other small form factors too numerous to mention. For the past 15 years or so, PC/104 and its brethren have dominated rugged, deployed systems.