Automated service installation

[zzantozz]

Suppose I'm running a Linux guest, and I want to treat my OS as expendable. I create a separate virtual disk to contain my home directory and mount that at /home/<user>, so all my personal stuff is taken care of. But what about all the services I run in the VM? If I'm running Apache and MySQL, have custom entries in /etc/fstab and /etc/hosts... and so on, I don't want to have to go through all the steps of installing and/or configuring all those things again. Is there a relatively simple way using VirtualBox or maybe some sysadmin tool that I can keep a "bootstrap" config so that I can install a new OS, run the script, and have my system configured identically to before?