It really depends upon what you want.
1.) Do you want the text searchable? In case someone remembers a line, but not the title...
2.) Are you going to be adding/updating them frequently?
3.) Do you want an admin interface, or not?
4.) Are you comfortable with XML or mySQL or CSV?
I'd say, use a mySQL database if you want scalability with an admin interface. Use XML if you know it, and can manipulate it in PHP (PHP 5 makes it easier). Use simple text files or CSVs to store them if you need a "quick & dirty" way to do it.
~Brett