Real programmers use Proggy Tiny. Proggy Tiny is well-proportioned and is the smallest programming font I could come up with while maintaining distinctive characters and good readability. I use this quite often where I want a high information density.
Use at point size 9 (bitmap font), 12 (truetype), or 16 (mac truetype)
The bitmap .fon version of this font includes 2 font files. One is the ANSI extended version, and the other is OEM extended. The latter is a console font and can be selected in console applications on Windows machines.