I’ve recently started to use NWCHEM (for access to some modern tasty tasty functionals). I really like the input deck format - much cleaner and more sensible, IMHO than the ‘concise’ header that one uses in Gaussian. However - it looks totally sterile as pure text, so I spent a little while learning how to write my own vim syntax file.
While I was at it, I wrote much cruder versions for Gaussian .com / .gjf formats, and one to do some basic column highlighting for PDB files.
As usual, made a quick gist, and if I ever get around to making these files less crude, will update there!