The DIR_COLORS file, installed in /etc by fileutils RPM packages includes the following line: DIR 01;34 # directory This means that directories in /bin/ls output will appear in bold blue over whatever background color is set in the terminal. Quite often that background color happens to be black (such as in VGA text consoles) or another dark color. The way the human eye works and the way screens and monitors are made to match it, blue only accounts for 11% of brightness of white (while it's 59% for green and 30% for red). See, e.g., http://www3.ncsu.edu/ECE480/480_tvc.htm for details. This means that typical human beings (not just me) will have trouble reading blue on black. (All this to say that this is not a simple matter of taste.) The implication of this is that if blue is to be chosen as a foreground color in DIR_COLORS or elsewhere, then a complementary background color has to be specified too. White and yellow are good choices. Therefore, I suggest the following line for DIR_COLORS: DIR 01;34;47 # directory or maybe as a second choice: DIR 01;34;43 # directory This would keep blue as a foreground color and cause the least surprise to everybody that is used to it. Those already using a white background will not even see the change. Those using a dark background will no longer have to damage their eyes to read it.
This setting is pretty much the standard (it's the default from fileutils, and [aside from Red Hat Linux] used at least on Slackware, Mandrake, and FreeBSD if you turn on ls colorization). Having just individual words appearing with a different background color looks odd. Feel free to do this on systems you're maintaining, but we don't want to diverge from the standard that far.