The hardest part of building this cabinet is trying to plan for the future - What tools will I own? What tools will I eventually sell or outgrow? I just don't have the answers to those questions. So, for now I think I will plan to utilize as much space without planning around any particular tool.
I thought about storing the planes vertically, but there seemed to be so much wasted space. Upon rotating the planes horizontally I can see how shelves and cubbyholes (for the smaller planes) will let me use more space. I will then put small doors over the larger planes so I can store smaller tools (chisels, rulers, etc.) on both sides of those doors.