Hi Chris,
I found using Vagrant with X stuff to be not as useful as I had hoped for.
(i.e. the standard boxes are headless and the script installs all the X stuff afterwards via the sw/extras/bootstrap_vm.sh script).
To boot the box with graphical interface uncomment the "vb.gui = true" line in the Vagrantfile.
You probably also need the virtualbox guest utils to resize the window properly, etc...
Also using this on windows does not make that much sense actually, since it will mount the paparazzi folder and it then has different line endings....
If you are on windows it makes much more sense to set up a "normal" desktop Ubuntu VM and install the stuff there as usual.
Hope that helps,
Felix