RE: Save the font setting (Emacs Windows)

[Drew Adams]

    >> (set-default-font "-outline-Courier New-normal-r-normal...

    > Thanks, that works when openning emacs normally but when open emacs
    > from emacs (e.g., Control+x 5 2) it reverts back to default font.

    The variable default-frame-alist controls the fonts and such for
    frames created this way

Library frame-cmds.el can help here:
http://www.emacswiki.org/cgi-bin/emacs/frame-cmds.el.

After you get a frame the way you want it, no matter how you tweaked it
(font, background,...), you can save one or all of its parameters in the
value of `default-frame-alist' (or `initial-frame-alist', or any other frame
alist) by using command `set-frame-alist-parameter-from-frame' or
'set-all-frame-alist-parameters-from-frame'. You can use option
'frame-parameters-to-exclude' to exclude some parameters from copying by
`set-all*'.

After you have updated `default-frame-alist', use `M-x customize-customized'
to go to its Customize buffer and then save it for future Emacs sessions.