As much as I like Bitstream Vera, the font has a problem: it's too light on Windows 2000. Text in 12 point Vera Sans Mono is a vast grey field rather than crisp black text.
The problem is Windows 2000's font anti-aliasing. Windows XP does a much better job. The image above shows an example; lowercase 'x'. Notice the absence of black pixels in Win2k? I wonder why Microsoft's own fonts don't have this problem; different hinting?