Tip for wxplot2d in wxMaxima 0.8.4 (Maxima 5.20.0)
set_plot_option([gnuplot_preamble,""]);
will get wxplot2d working, but instead of typing it
every dang time you open wxMaxima,
put that line in your maxima-init.mac file.
Where's that? On my xp box, the file is in
c:\documents and settings\<username>\maxima\
If a file search doesn't locate it,
create it there (as a plain text file).
(hopefully this problem will go away soon)
-dae