I didn't realize there were so many model railroaders on the board here! What scale are you going to run? I'm old school DC on my layout - if I had it to do over again I maybe would go DCC, but I've got so many locomotives now that putting decoders in them all would be expensive. And I know several folks who have had issues with DCC -- decoders that quit working, entire layouts that quit working due to glitches, etc...I'm able to run multiple unit lashups effectively by putting locomotives that are roughly the same speed together. And troubleshooting is easy w/ DC -- just wires.
Nice layout JP!
That said, my layout (n scale) is decent size, and it would be cool to run multiple trains in different directions.
Here's a couple shots of my layout:
