If it will help anyone, I'd like to chip in with a memory/note-taking technique I am using at the moment. Mindmaps. I find it extremely powerful for very fast information retrieval, since it's inherently hierarchical. I do digital mindmaps, using Freeplane. I use it for storing key ideas from books, articles, workflows, step by step howTos, programming snippets, even for my own thoughts. You name it.

Only downside I can think of is that my memory no longer has any incentive to retain the information I come across so you could say my memory only gets worse, using this technique. Does anyone know of any studies on long term effects on memory when storing information externally, rather than forcing your brain to do it itself?