During my undergraduate physics degree I started by taking notes on paper, however I started to notice I was struggling to read my handwriting. I soon moved onto typing notes, in openoffice, using its built in equation editor, and attempting to draw diagrams with a stylus on a graphics tablet.
After a year of doing this I realised it was a bit of a struggle to keep up, but in the mean time had learnt LaTeX. Then I stumbled upon an even better solution, type the notes (and equations - managing to keep up with the lecturer), and leave a space in the notes for the diagrams (i.e. setup the environment and name them in ascending order fig1, fig2 etc), but draw the diagrams manually on paper. Then I could copy the diagram at a later point into the LaTeX document using the graphics package of my choice (and for the particle physics module, feynmf for LaTeX proved particularly helpful).
It is actually possible to keep up with the lecturer, so long as you reach the point that when typing you don't have to think about what your typing for things such as \alpha and so on. You also have to be fairly accurate with your typing, and be able to visualise how the notes are going to look without compiling them.
Overall, if you don't think yourself capable of that, stick to pen and paper, if you do and you have troubles reading your own handwriting when trying to scribble quickly (I can type much faster than I can write legibly), then it is worth looking into.