Just me, but I'd just as soon ride on a knobby tire with lots of low knobs and a nice light supple sidewall as a heavy "flat proof" slick tire with as stiff sidewall. I am not too familiar with the Continental Travel Contact, but it looks like it might fit in that latter category.
Lester already mentioned a couple XC race tires, but there are others that would work. I have done some mixed surface tours where I wound up doing quite a bit of riding on paved surfaces in between dirt sections and found XC race tires to roll surprisingly well and to be very pleasant to ride, something I'd never say about heavy stiff sidewall tires. I usually tour on skinny slicks these days, but found the fat xc knob pretty pleasant to ride on.
Compared to the Marathon Pluses that I once tried for a short while before taking them off and selling them, the XC tires were a joy to ride on. That said I love a supple sidewall and a responsive ride and some others may not even notice the difference or get what I am talking about. Note that this isn't just about the weight of the tire, but there is that too (the MPs were crazy heavy in addition to having a really stiff sidewall).
I'd suggest that depending on how and where you ride sitting upright might be a bigger efficiency handicap than the xc tires are. It is your choice, but there is no reason that you have to sit very upright on your mountain bike, mine are typically set up with the bars pretty low.