FlyBoys Kneeboard - small, has the option for either clipboard or loops, good organization and small pockets. Also prevents any paper from flopping around due to the wind. Even better, once you are doing IFR training, a hood like the Feather Hood (which, imo is totally overpriced for a piece of cardboard, but it works) folds and stores easily in it.

I'm not a fan of the tri-fold style as it quite a bit bulkier and gets in the way when folded out.