How to Take Notes in the 21st Century

I have been trying to figure out how to best utilize technology to take notes.  Since I am a college student, I have the task of taking notes for classes.  I also go to academic talks.  I also attend other sorts of meetings where note taking might be useful (for example, church meetings).

The traditional way is to use pen/pencil and paper.  There are various techniques for efficiently using ones notes, and that I will not go into.  In the past, I have only needed notes for a class during the period I took the class.  After I had taken the final exam, my notes became useless to me (from my perspective).  As I have progressed in my education, I have needed the information contained in notes more and more, especially in the future.

As I researched this subject, I have found that this is why people use filing systems.  I probably sound quite naive in saying that, but I guess I never had the study skills to get to the point of needed a file system.  I put together a quick and simple filing system for some of my math notes.

With some other subjects, however, I found that a filing system seemed too inefficient.  For example, with my study of the scriptures, there are so many different topics and categories to place notes in that creating a physical filing system would be a lot of work; also, I don't have space in my apartment for a large filing system.  I have, therefore, been playing around with electronic solutions to this problem.  Having all of my notes in an electronic format would benefit me because I would be able to arrange said notes with much greater ease.  Further, if I needed to put together a talk, as I did in this post, it is easier to copy and paste bits from document files than it is to copy those bits from a printed source.  Finally, I can access my filing system via a portable device and call up information wherever I go; with a large physical filing system I can't do that.

I would be interested to see someone who has this concept down better than I do.  To a point, I am collecting things electronically with the expectation that in the future there will be something much better which will can utilize my electronic files.