I too find that using a mouse and menus slows me down when typing math. I
discovered though that it is a little appreciated fact that virtually all of
the symbols in Microsoft's Equation Editor are available from the keyboard very
easily.
For example, Alt-g then a letter produces a Greek letter. (I'm sorry, but I am
typing this from a Unix system, so I can't check to be sure I'm getting the
directions exactly right, but this is close!) Something like Alt-s gets you
symbols, etc. I've gotten to the point where I can type math with MS Word as
fast as I can in LaTeX.
Actually I discovered this after I bought MathSoft's MathType which is the
extended version of the same basic product as Equation Editor and which works
with other programs. In the manual for MathType are all the keyboard shortcuts.
They almost all work in Equation Editor. To find them in MS Word is tricky. You
have to start Word, then get Equation Editor going, then call up Help. Look for
keyboard shortcuts.
With Word, Equation Editor/MathType, I finally feel that one can produce high
quality math documents without LaTeX.