I made a little convention of marking 's' and 'd' as the top and bottom of a range of lines. Then I define several handy utilities like:

  "	Shift-Alt-Z    #-comment range 's,'d
  inoremap <S-A-z> <Esc>:'s,'ds/^/#/g<CR>:noh<CR>
  inoremap ^[Z     <Esc>:'s,'ds/^/#/g<CR>:noh<CR>
   noremap <S-A-z>      :'s,'ds/^/#/g<CR>:noh<CR>
   noremap ^[Z          :'s,'ds/^/#/g  <CR>:noh<CR>
  onoremap <S-A-z> <C-c>:'s,'ds/^/#/g<CR>:noh<CR>
  onoremap ^[Z     <C-c>:'s,'ds/^/#/g<CR>:noh<CR>