I'm in the same boat, every time one of these threads pop up I try a few different fonts recommended here but I always end up going back to DejaVu. It think it looks pretty good, it has good Unicode coverage, it's supported out of the box on most distros...

It's weird because I can be pretty snobbish and opinionated with a lot of programming-related stuff (I use a very expensive keyboard, a large 4k screen, a heavily customized editor and window manager etc...) but when it comes to fonts I really have a hard time finding a real improvement with some of the very expensive fonts people are recommending in this thread compared to good old DevaVu.

I would be very interested to read an article that would explain in details what makes certain fonts better or worse than others, especially for programming.