Ensure a given module (set) is enabled on a dev site
(It was me who wrote the instructions for the hook_init() hack at http://drupal.org/node/206368.)

Recent module-level ways of supporting this workflow are underway at the Environment module, and the Production check &amp; Production monitor.

I feel they will rapidly become too bulky: Do you really need to enable a module to ensure another module is turned off? 
But, at least they may be able to provide a few conventions for us, like putting the list in local.settings.php or equivalent. 
I hide per-instance configs in in my site_aliases.drushrc, which is my alternative to local.settings.php

I'm not going for another script you have to call, unless it's part of a fully automated workflow.