I'd suggest to have the following applications by default (by categories from Applications Menu):

1) Accessories: xarchiver, xfce4-appfinder, mousepad;
2) Games: xlennart :)
3) Graphics: ristretto;
4) Internet: iceweasel, transmission-gtk, xchat, netman or dhcpcd-gtk;
5) Multimedia: parole, xfce4-mixer, xfburn;
6) Office: zathura;
7) System: gparted, synaptic.

What I am not sure about:

I am currently using file-roller and evince from squeeze and am trying to avoid gtk3
where it possible because of huge dependencies (mostly), ugly theming and occasional
instability. These two requires about ten packages from squeeze overall and cause inability to install
more recent versions of GNOME stuff (like epiphany-browser, gedit and so on).
Thus, as suggested above, I would give a chance to xarchiver and zathura.

As for office, I'd go with LaTeX and sc but LibreOffice is of course easier to use.
I wouldn't include office suite to a default installation.

Count also core xfce4 desktop packages: xfce4-panel, xfdesktop4, xfwm4, xfwm4-themes, xfce4-powermanager,
xfce4-screenshooter, xfce4-terminal, xfce4-notifyd, xfce4-volumed, xfce4-taskmanager, xfce4-session,
xfce4-settings.

I reckon all of these simple yet powerful things will fit to a single (Live)CD. Also I think it is a good idea to keep
Xfce the same as it is in Debian (or upstream).

And also I'd go with vim-tiny as it is really close to the original and without nano by default.

My two pennies worth,

Mitt