Brandon Savage has a new post to his blog today looking at some of the more essential settings to check out in your php.ini file when configuring your install.
When setting up a web server with PHP, there are a number of settings that are critical to consider. PHP 5.3 contains both a development INI file and a production INI file; however, users of older PHP releases (or those who don't have direct control over their INI files) will want to pay attention and make sure that certain settings are configured.
Settings in his list include:
These are just a handful of the settings you can configure in your php.ini. Check out this list for many, many more.