I prefer instant coffee too, which is convenient. My problem is that I like it made with 50% milk (and sugar - I usually keep very quiet when I'm around real coffee drinkers) and I've yet to find a powdered alternative I like. When I'm car-camping I take a vacuum flask of milk. If I have to carry it I drink oxo-cubes instead.

I've recently come across the "cappuccino" packets. I find the Nescafe brand is drinkable in a pinch so I'll try carrying that this summer. (I've also tried a cheap Asda version but it tasted a bit chemical.)