This vimspell module is really very good. I now have Word-style on-the-fly spell-checking. In vi.
I should look at the source and see if I can finally implement my “tell me the word count in the status bar if I idle for more than 0.5 sec” dream feature.
(It messed up a bit in HTML mode, but there’s an answer in the FAQ about that. The clue is in the screenshot.)