Don't put code in the DB.

Upgrades. Use the install profile API to trigger content-type creation.

DBScripts projects. Can try to merge dbs. A little sketchy.

Municat.

Macro module with devel can drive Drupal.

Ways to map relationships between nodes:
- Taxonomy
- CCK Node Reference
- Relativity Module
- Menus

In 6, menu alter is a nice new hook.

Pathauto a great way to jump in the way of tags

In Drupal 7, CCK fields can be applied to other Drupal objects. Then can use CCK field perms to manage access.