I've been using Visio lately (an old ebay version) to do technical-manual illustrations. If you export a drawing as an .emf file, into Word, the linework is very good.
Anyhow, I have a cheat sheet of symbols, not world-shaking but fairly useful. I just copy/paste into new projects.
ftp://jjlarkin.lmi.net/_Parts_1.jpg
ftp://jjlarkin.lmi.net/_Parts_1.vsd
Note that this is for simple illustrations and block diagrams, not actual schematics.
What do you use for stuff like this?
John