If your goal is resale, this domain is worthless. Pretty much no net.co has any real value.
Owning "Apple" is defensible in many situations because of the generic usage, however in this specific case the domain is parked with many TM infringing ads. I would just drop it.
"Apple" is an age old generic noun in the English language. Can Apple Inc. really "own" it in that way? I'm not a lawyer but its against my common sense. Maybe you could use it in a way that violates trademarks but Apple Inc doesn't own the English language, IMHO. Or is Apple Inc gonna suite the Church because "apple" appears already in the genesis (Eve and the snake etc.)
And anyway, the corporation is "Apple" but the fruit is "apple".