Typically, there are only three start-up scripts that I immediately configure.

/etc/profile holds variables and command arguments for the sh, bash, ksh, and zsh shells. I edit the PATH so that any directories with my own software are added. The PATH is a list of directories that are automatically searched for an executable when you issue a command. I also add $QTDIR and $KDEDIR for my KDE installation.

/resolv.conf holds your network variables. I will typically add a second nameserver so that it reads:

domain foo.com
nameserver *.*.*.*
nameserver *.*.*.* 
Lastly, I will edit /etc/inetd.conf. /etc/inetd.conf holds the startup commands for all of your internet services. Since my computer is a workstation, and not a server, it is a good idea to turn off ftp, telnet, etc. Do this by commenting out the command by placing a "#" in front of it.

While it's not a start-up script, I also edit /etc/fstab. /etc/fstab holds a list of filesystems to mount. If you add an entry for your CD drives, you can mount them with a much simpler command.

First, make the mount points /cdrom and /cdrw by issuing:

$ su
# mkdir /cdrom
# mkdir /cdrw

Next, add the following two lines to /etc/fstab:

/dev/scd0 /cdrw iso9660 defaults
/dev/scd1 /cdrom iso9660 defaults

Note, your scd0 and scd1 will be different depending on your drive configuration. Primary master is /hda, Primary slave is /hdb. Secondary master is /hdc, and Secondary slave is /hdd. If your drives are SCSI (or emulating SCSI), they will be scd*.

Now, you can mount your CD drives with the simple command of:

$ su
# mount /cdrom OR mount /cdrw

Before, the same command would have been:

$ su
# mount /dev/scd0 -t iso9660 /cdrw OR mount /dev/scd1 -t iso9660 /cdrom

Likewise, you can unmount a drive by issuing:

$ su 
# umount /cdrw OR umount /cdrom