Like many other home layouts available space is always the biggest issue.  I envy those who have large basements and are able to dedicate their empires to the entire space.  This is my second layout that I have built in my current house.  The basic design is a U shape with the overall size being 9' x 12'.  Currently I am building an extension to the layout with two 2'x10' shelves.  The layout height is 50" above the floor with 2" x 4" construction and 3/4" plywood for the deck. All the track and turnouts are Atlas code 83 with an exception of one or two curved Peco turnouts.  I am using MRC Prodigy Advance Wireless dcc system.  I have been using the system since 2004 and  I am very happy with it.  It meets all of my needs plus it's easy to expand if I need to later.  I picked this system after seeing a friend use Digitraxx and he wasn't very happy.  The buildings consist of plastic and laser wood kits.  I do have several buildings that I scratched built using plastic styrene.  I really enjoy using this material and find it very easy to use.  The track plan is a basic double track loop around the outside with a small yard, industrial spurs, roundhouse and turntable.  I built it this way to handle my large steam locomotive collection.  The minimum radius curve is 28" with the max being 33".  I also have a strong interest in operations and I am setting up the layout for future ops sessions.