The Living Thing / Notebooks : Diagrams, of the kind I need, a practical guide to the creation thereof

Awesome examples

Gallery of concept visualisation: gallery of methods for explaining complex ideas; everything from exotic 3d stuff to crayon drawing and sticks.

See also interactive visualisations.

Tedious howtos

Sketching vector diagrams for your reports. More painful than it should be.

Here’s the stackexchange list.

Here’s my list, in descending order of priority

Notice there are no commercial entrants in this race?

I’m too poor for any Autodesk product, and unconvinced of their utility unless I wish to build some kind of major concrete structure.

I did buy Omnigraffle, the much-touted diagram editor for OSX. What a disaster; expensive, unintuitive, over-engineered. Like they ripped of xfig, took out the API and compensated for it by putting bezels on the icons. If you want to waste hours with horribly inscrutable drafting products, there are many open-source options available that can give your that experience for free.