Hmm... I take all my notes in LaTeX as well. For me, I found that it was more a matter of having the correct macros than any inherent slowness in the LaTeX type

Hmm... I take all my notes in LaTeX as well. For me, I found that it was more a matter of having the correct macros than any inherent slowness in the LaTeX type setting system. My preamble grew to about 130 lines before I was really able to type effectively in class. However, the benefits of this approach are undeniable. It halped me become good at LaTeX but more than that it made my notes easy to archive, retrieve, share, and use in general. Referring back to old theorems is a lot faster when you have Ctrl-F at your disposal. The key is that if you write a similar thing more that ~3 times, make an emacs abbrev for it or a latex macro for it.