Agreed. LVM's great. It should be easy to install with, and probably default for users who don't understand what it is... after all, they're most likely to find out that they've created partitions that are too small (or big).
actually it is already possible with the alternate-cd's text-mode installer. But it was great if this was also possible in the graphical installer.
also great if encrypted lvm was accessable trough the graphical installer.