I see both sides to this one.

Because it seems that everything that can possibly come up has come up in the past, if everybody just did searches this site would essentially become a database. It is good to get new thoughts on old topics occasionally. BUT asking a question like that is way too broad and does come up a lot. An example of a good way to phrase your question would be. What is the lightest weight sleeping system I could get away with in the (insert where traveling) in (insert conditions (season, altitude, length of trip, on/off trail, solo or not, etc...)). This type of question will recieve the best response in the beginner section also.