what to install & do :?

HI Guys

I want to create a minimal openbox system using the ubuntu mini.iso. Installing only the base system with whats listed below will I need to install anything else ??

"openbox, obconf, obmenu, gtk-theme-switch, gtk2-engines, lxappearance, tint2, xinit, xorg, gdm, synaptic, thunar, feh, xterm, gedit, nano, lynx, network-manager"

Will my system boot straight to gdm and let me login to openbox on it's frst boot or will I need to edit any files before that happens ??

I have used the mini.iso before, but have only ever installed a desktop from the list given. Your help will be much appreciated. Thank you.