This is quite exciting! I have started using Inkscape to draw diagrams for use with LaTeX a few years ago and I like it a lot. (There is an option to export PDF+LaTeX with allows you inline code.) For more precise stuff which requires programmatic handling (e.g. algorithm visualisations) I can just write out an initial SVG and edit that by hand afterwards. Maybe now is a good time to look into some customisation options, it seems there are lots of them with the 1.0 update.