I like vim and auto-completion
But the two don’t come together out of the box… unless you count omnicomplete. But I don’t, because it just feels broken or half-implemented to me. And I especially hate the ctrl-x + ctrl-o combo it uses.
A better alternative: pydiction
http://www.vim.org/scripts/script.php?script_id=850
Installation is easy. Just put the .vim file in ~/.vim/after/ftplugin/ and put the dictionary file somewhere else. Then add two lines to your .vimrc and that’s it.

Just hit tab and it will give you a drop down menu allowing you to auto-complete if your cursor is sitting just after a keyword.
Posted by admica @ 20 September 2010