A standard in terms of optics and use

[Joel Tlumak <JT@JMBM.COM>]

One thing about standard lenses that no one mentioned is the
high optical quality of the 50mm focal length.  Photographers
can debate until doomsday about what should or should not be
"standard" focal length, a discussion which is irrelevant.  But
what is not irrelevant is that a photographer gets what appears
to be the highest optical lens quality from a fast standard 50mm
lens at the lowest cost -- the lowest cost of any lens at any other
focal length.  

A photographer without much money or someone new to
photography can acquire a camera with a 50mm f/1.8 or f/1.4 at
an incredibly low price and that lens will match the quality of any
other marquee 50mm lens and permit the photographer with
that single lens to do low-light work, non-macro close up work
and virtually anything else.  In those terms, the 50mm is without
question the standard for 35mm cameras.