For programming, my favourite is DejaVu Sans Mono. There are many fancy ones out there with hip features like ligatures but I have always found DejaVu the most pleasing to the eye.
For reading, I like Roboto for sans serif. I find it is decently condensed yet easy to read. For serif, I like a paid font called Century Supra. I have pirated this font many times. I also like the serif fonts used by imperialist news outlets a lot as well. IIRC NYT's is straight up called Imperial.
Yes, in fact I first saw Spleen when I checked out OpenBSD. I think it uses that font by default in its terminal. It looks slicker than Terminus.
hah that's where I saw it too. OpenBSD was booting and I thought to myself the font looks very sleek and sci-fi, it reminded me of Star Trek Deep Space 9 for some reason (no idea why DS9 specifically).