One solution to the problem of which drawing program to use with lyx when equations need to be added to the figure might be the following.
Assume that an .eps figure is displayed on your screen from lyx. Move your cursor to the point on the figure where you want an equation. Now type in the equation using lyx as if you were typing in lyx normally. SIMPLE! ? There are numerous problems with this idea but it may satisfy the needs of lyx users in some circumstances. When it doesn't you go back to the current methods. Of course implementing this feature is another matter. In particular it is important that the equation shows up in the final output in the same relative location that it does on the screen and I suspect that ensuring this is hard. So, any chance this will be added to lyx 1.2.2? :-) Ralph