I am the new kid here but....
My advice to the MDF crowd: Try to use Baltic Birch plywood instead!
1.The birch ply will hold up much better to moving (as in moving to a new house or from the basement to garage.
2. Small kids and teenagers cannot damage the MDF with stuff
I am not referring to plywood that can be purchased at Home Depot or Lowes. This is a specialty plywood for woodworkers. It comes in 12-15 plys. Yes, it can be expensive but look at online sources or the yellow pages. I called 'Industrial Ply' here in town and not only did they have it but in a range of size and thickness. Paying cash also got me a discount.
Additionally, I see alot of folks buying metal needed at Home Depot, etc. I paid a little more for it but I went to 'Metal warehouse' (a small mom/pop store) here in town. (We need to keep these people in business! personal rant) I found them in the yellow pages and also paid cash. I was able to get nickel steel and chromium steel rods for approx. 20% more than I would have paid at a box store. but the bar was complete straight
I work in the Aerospace industry and am a woodworker as hobby. I smacked one project (a jig for holding work while using a router table) by dropping a 2x8 on it.
If you are going to spend the time and effort by advice would be to at least use the birch ply for the vertical components and the motor holder, make the base out of MDF if you must. If you are building something with a large table, try to find a broken plotter to cannibalize for the horizontal runners (chrome steel with very tight tolerances)
Supprisingly enough, Menards sells 3/4" baltic birch. It is only sanded on one side but that side is not bad and you do have the 14-15 ply. A very good stable wood.