Well the Atom isn't really a mountainboard its a kind of long board that MBS made. If there are no wholes to mount the bindings in the board you have to drill.....
You'll find that the channel trucks on a pro 12 or pro 16 hold better when going a high speeds aposed to a skatetruck.
Matrix Trucks, Alum. Hubs, F3s and T3s are the best you can get right now from mbs. If you don't see what you like there check out GI.
As for a board it depends if you are a big guy or no, a smaller board will flexy get fast, so a pro 16..
It depends on your size and what you want to spend, the cheaper the board the faster it will break.
I say get the best you can so you don't have to buy or upgrade till the new stuff is out....