[platz]

Check out http://haskelllive.com/environment.html

I don't use Syntastic, but haskellmode-vim and ghcmod-vim integrate nicely with ghci, and neco-ghc gives autocompletion.

I don't use tags files or other project-level stuff, the above is good enough to get started.

Also once you have ghcmod-vim you can map a key to tell you the type of an expression:

    au FileType haskell nnoremap <buffer> <F12> :GhcModType<CR>

It does take some work to get all these things installed, however.