What software do HNers use to make good diagrams? We have one suggestion for TikZ so far, which looks nice, but I don't really want to get out the TeX hammer for every little diagram.
http://www.iobound.net/iocopy-talk/
Another thing I experimented with for the first time is doing all the slides in html / css / js. The jQuery-Presentation plugin [1] works as advertised, and with css there was considerably less hairpulling when it came time to start tweaking layouts and positions. The content for each slide is written in markdown. You can see all the source for the presentation here [2].
(I can't wait for some web-based presentation software so I can finally ditch Powerpoint, but right now, with the extremely limited palette of animation ability on all of them, I'm forced to stick with PowerPoint.)
For papers, posters, and other static media, I use Inkscape, which I love. And every once in a while, for a system architecture diagram that I need to crank out really fast, I'll use Dia, which is much less flexible, but ideal for that task.
I try to use the best tool for the job though.
Two weeks ago I had to make a code-based introductory presentation and I used showoff instead ( https://github.com/schacon/showoff ) since it comes with syntax highlighting and the slides are just a text file. It took me maybe a couple hours to learn the ins and outs, but then it was easy.
I've heard that the Mac app is good, too, but I haven't used it yet.