Script to check webserver daily


I am now going to be managing several RH servers acting mainly as web
Each server will be running PHP, mySQL & Apache.

I'm looking for guidance on what sort of system things I should be
watching on a daily basis to best maintain these servers.

Ultimately I'd like to come up with a script that can run a daily
check of major systems on the server and email me a summary but I'm
not sure what all I should be monitoring. Things like disk space,
service status are obvious...I'm sure there's more out there I should
be keeping track of.

Any guidance or example scripts would be great.