I have been toying with setting up a new layout for the past few years, and have finally made a few decisions about the direction I want to go. I am using the "Beer Line" track plan from Model Railroader magazine, translated to N scale, and configured as an around the room shelf layout, rather than their free standing method.
I was interested in creating something modular (N Trak, oNeTrak, Fremo N), but after sketching a few designs that would fit in my layout area, I gave up on that route. The problem is that I have a slightly smaller than 8' x 12" room, and adherence to the standards for those modules really impacts what kinds of things you can do in such a small area.
This weekend I cleared out most of my old Ham radio gear and took down some built in shelves that I had put in. I installed those double slot shelving rails and got the brackets on 2 of the walls. The plan is to build the trackplan in the "J" configuration for now, then as I have time/interest/money, to separate and rotate 2 of the sections to the opposite wall and build new sections to bridge the gap.
3 weeks ago I started experimenting with construction methods for the smaller of the 2 shelves. I had some half inch plywood, and some three quarter plywood leftover from some of the other home improvement projects. That would turn out to be a decision that would bite me later on...