" Always edit a file on gf, but be nice and ask
map gf :<C-U>call GoFile()<CR>

function! GoFile()
  try
    normal! gf
  catch /^Vim\%((\a\+)\)\=:E447/
    let q = substitute(v:exception,'^Vim\%((\a\+)\)\=:E\d\+: \(.*\)','\1','') . ', would you like to create it?'
    try
      buffer <cfile>
    catch /^Vim\%((\a\+)\)\=:E94/
      if confirm(q ,"&Yes\n&No\n&Cancel",3) == 1
        exec 'edit '.expand('%:p:h').'/'.expand('<cfile>')
      endif
    endtry
  endtry
endfunction