From ViM 7.3 onwards, most of the common programming languages are supported (/usr/share/vim/vim73/autoload/...). To make them work automatically, update your vimrc with:
autocmd FileType python set omnifunc=pythoncomplete#Complete
autocmd FileType javascript set omnifunc=javascriptcomplete#CompleteJS
autocmd FileType html set omnifunc=htmlcomplete#CompleteTags
autocmd FileType css set omnifunc=csscomplete#CompleteCSS
autocmd FileType xml set omnifunc=xmlcomplete#CompleteTags
autocmd FileType php set omnifunc=phpcomplete#CompletePHP
autocmd FileType c set omnifunc=ccomplete#Complete
Use CTRL+ X O to close tags after typing the start of the closing tags.
For example:
This is a sample paragraph </ CTRL +X O will automatically complete the closing tag.
Simple as that
More information on configuring ViM: http://newbiedoc.sourceforge.net/text_editing/vim.html