Evan,

>How much empty space should I leave when packing for Devcon? What kind and how many goodies should I expect to haul back? I am planning to take a traveller backpack to devcon (one of those that zips open instead of a drawstring like a backwoods). It hold about as much as a normal suitcase. Should I bring a second one?

I always take an extra medium size duffle bag, folded up in my main luggage. Usually it comes in handy for bringing back stuff, and also for those dirty clothes that never seem to fit back into the same space. Then there's each day's supply of hotel shampoo, lotion, soap, etc... (no towels!).