I'm hoping to tap into some collective experience here, so **What (if any) utility tables, or common fields do you always include in your database design?**

An example is that I always include an `App_Errors` table to store any uncaught exception information in, and an `App_Audit` table which stores all the edit information.

I've mooted (in my own mind) the benefit of including `RecordCreatedDate` and `RecordLastEditedDate` on each data table but not come to any conclusion as to whether or not the information really will be that useful.

To give the question a bit more direction - My current focus is globally accessible web application ( think social networking ). 

Ta!