Modern fonts for technical documentation? There’s a good strand on Quora about this. The renowned typographer Erik Speakermann himself weighs in with comments (suggesting his own Meta—a fair call, be it his or not—as well as ) ITC Officina Serif and Sans. Other suggestions include DIN, which I have some empathy with as both my previous and current universities use it in their branding, and for open source alternatives, DejaVu, the Liberation set, and Prime.
And my current new find? Courier Prime. It’s great if you’re trying to do storyboard/script style pieces as it has italics as well as roman and bold, and is free (the designer just tells you to buy someone else’s).