The one that has a landing I can walk away from at the end???
Actually, after the rationalisation project (in Australia) the ADF will be more useful than VOR's. There will be very few VOR's outside the "J curve". And the ones in the J curve are mainly primary airports, where GA aircraft don't go very often.
Outside the "J curve" there will be lots of useful NDB's.
NDB procedure skills are worth maintaining. Its a pity that AsA are not retaining any of the commonly used training aids (at least in the Melbourne basin).