Which version of Excel allows that, Luke? It doesn't look as if Excel 2003
does. It will do that for a normal series, but not for a trend line.
For a trend line, all I could think of was to change the colour of font and
background, but that would make invisible not just the word "Linear", but
also the "(Series 1)" or whatever (i.e. the series name of the series for
which the trend line is drawn).