i've used everything from windows paint to adobe paintshop.I guess it depends on how fancy you want your panel.one thing i do know is there is lots of free software that will do the job and their easier to learn than the high end graphics programs
or you can use Corel Draw, if tomorrow you want to make professional layout from specialized serigraphy laboratory, you will must have a standard file format like corel draw or autocad
I had used Corel Draw in the past with very nice results.
You might also use MS Excel. It has a nicec set of drowing shapes and tools.
The easyer program to use is the one from abacom as mentioned in a previous post by Cluricaun. It contains standart shapes and scales. e.g. the scale of a potentiometer is given in many kinds, from 0 to 10 or from -5 to 0 and then to +5 as used in balance volume control or treble and bass etc.
I just tried the one from Abacom and some oft the paint programms you suggested,
but the programm from Abacom really impressed me.
I think I will stick to it in the near future.