Cubic lets you easily create customised Ubuntu and Debian ISOs

Cubic (Custom Ubuntu ISO Creator) is a GUI wizard to create a customized Live ISO image for Ubuntu and Debian-based distributions.

Cubic permits effortless navigation through the ISO customization steps and features an integrated virtual command line environment to customize the Linux file system. You can create new customization projects or modify existing projects. Important parameters are dynamically populated with intelligent defaults to simplify the customization process.

This is an incredibly neat tool, and it's given me the urge to see if I can create my own custom ISO with my personal defaults all set out of the box.