A hammock all the way!!!! Those of you who say its uncomfortable are doing it wrong. A hammock, tarp, and some rope are all you need and it all packs up very small. I frequently take hiking trips for 3-5 days at a time with less than a 50lb loadout. I dont think I could accomplish this with a tent and besides, who wants to sleep on the ground anway? Check out this site http://www.hammockforums.net/index.php
Lots of good information on how to correctly set up a hammock and what other gear you should check into.