I use gVim all the time, I like that editor very much (emacs is just way too much, if you ask me.)
But once in a while I install a new server and by default they generally turn off the modeline feature. This is because there are potential security risks in link with that feature (i.e. vim starts running whatever script is defined in the text files that you edit...)
Anyway, I most often forget about the command to enable my:
vim: <setup>
(I most often define the tab stops, corresponding shift width and eventually the syntax of a file.)
Only, on those new servers, that doesn't ...