s/\~\//\$HOME\//g - There's possibly a nicer way to make sure tilde expansion is done in the right places, but this works just as well and doesn't require extra thinking when I'm half asleep :P Added (^|:) to start, and ($|:) to end of all tests to make sure we're matching a full path. Also test for (and append if not there) a ':' at the end of $MANPATH; otherwise Linux systems tend to forget how to search system paths.

version 5.0
set nocompatible
set autoindent
set cindent
set mouse=a
set smartindent
set smarttab
set tabstop=3
syntax on
set sw=3
set bg=dark
set textwidth=78
set sm
hi Normal guibg=black guifg=white