I've heard that in general, down is always the way to go. However, I'm in an unusual situation. I'm going to try to travel the world for the next year or so, taking odd jobs as I go. Thus, the bag is going to be kept in the stuffsack until it's used. I may be staying in hostels for a month at a time. I know down bags should be stored hanging. That's infeasible for me. Would the artificial stuff fare better?

Anyway, I guess you should still have the down bag..... Who knows you could still be able to find place where you can store it hanging

i am still for the down bag, but let me give you some points to consider. down bags reduce weight and stuffed size, weigh less and compress smaller than synthetic of the same temp. rating. comfort and durability favors more in down bags, than synthetic ones. although you really need to keep down bags dry all the time, if you see yourself having more wet trips, synthetic bags are better because it can stand wet environments. down bags are also pricey.. just think of your personal requirements, what works for you.. enjoy your future trip!