I like the rocket board. Float in powder isn't that great due to the wheels but you can avoid line ups at the chair because thanks to propeller power you can just ride up the hill. Downside is that you have to refill the tank once or twice a day.
A 2 x 4 will be better for framing or stud work, but if you are looking to create structuraly support, a 2 x 10 double layered will be perfect, unless you go to steel I beams. Since you said board, I assume you mean wood.
I've heard some good reviews on the dry erase smart board. Whether or not you choose to use ink you can write on it and then hook it up to an external display to give a different perspective on a subject.