I don't fully understand inductors. Saturation, field strength, ampere-turns, magnetomotive force - all that is pretty mysterious and I usually "design" an inductor or transformer largely by trial and error. However, having recently built an inductor tester using a pulse generator, I thought I'd have a go at seeing how things like inductance and saturation current depend on turns and air gap.
I've assembled the results into a PDF file, available here. Nothing probably too amazing, but I found it useful to go through the measurements anyway.
06/02/14: See also my page on inductor design.