Although I am not a programmer, I do prefer monospaced fonts, and my favorite right now is the bitmap font Tamsyn. I recently discovered it via the Arch Linux wiki and I now have it set up as the font for my Xterm windows (set via .Xdefaults).

My favorite TTF monospaced font has got to be Consolas, which I use in Windows as the font for Foobar2000 and Notepad2 (I keep everything in plain text).