I take a LOT of notes, and I loose a LOT of notes.   I find myself throwing away little bits of paper with random writing daily.  Collect your thoughts in one classy place: a Moleskine notebook.

Prices vary and they are vailible in almost every bookstore in the world.

http://www.moleskine.com/en/collections/model/product/notebook-large-ruled-orange-yellow-hard
AND here is a great system to keep it organized:

;