How Do You Read and Take Notes?

I'm curious how my fellow academics (and other book lovers) approach reading and note-taking, particularly for research. Do you take notes while reading, or mark your texts somehow and then go back later to take notes? If you mark your books, do you underline, make marginal notations, use key word summaries, or argue with the author in the margins? And when (if?) you take notes, do you summarize the overall thrust of the book or article, detail the argument (in your own words or theirs?), record key quotes, or just take note of particular points that are directly relevant to your current research? Do you organize your notes in any particular way? Do you print your notes off for use, or just use them digitally?

I've tried a number of different methods over the years but I've never settled on one that really meets my needs. At times I've underlined excessively and filled the margins of my books with questions and comments. At other times I've read with an open notebook or even in front of the computer and taken my notes while reading. Lately I usually just make quick little pencil marks in the margins (< to mark the beginning of a significant section; - for the end; * for particularly noteworthy quotes; ! for surprising statements, whether brilliant or ignorant; and ? for confusing points), with only occasional marginal notations. I then go back through later and type up some notes based on these marks.

But I'm very inconsistent in how much detail I record, especially when I am first starting research on a new subject and am not yet clear on what is significant or what my conclusions are likely to be. I've ranged everywhere from typing out in full every quote I think could possibly be useful (i.e. when I've got a monograph on inter-library loan and can only keep it for a few weeks), to recording only the barest summary of a book's contents and then just consulting the book itself as needed. No doubt there is some happy medium between those, but I've yet to find it.

Anyone want to share their own methods? Frustrations? Dirty little secrets?