EditPad Lite has a nice feature (CTRL-E, CTRL-I) which inserts a time stamp e.g. \"2008-09-11 10:34:53\" into your code.
http://kenno.wordpress.com/2006/08/03/vim-tip-insert-time-stamp/
Tried it out, it works on my mac:
:r! date
produces:
Thu Sep 11 10:47:30 CEST 2008
This:
:r! date "+\%Y-\%m-\%d \%H:\%M:\%S"
2008-09-11 10:50:56