OOO Thubnailer is a Nautilus utility that provides thumbnails for LibreOffice / OpenOffice.org documents, presentations, spreadsheets and drawings.
Its description also mentions that it should work with Microsoft Office files, but this didn't work in my test (it seems this occurs because I've saved the files to .doc/docx using LibreOffice).
Besides the thumbnails, OOO Thumbnailer also displays the file type icon in the bottom right corner of the thumbnail.
The package was recently updated to work with LibreOffice too (previously it had OpenOffice.org as a depenency) and to support GNOME 3 / Nautilus 3.
To install OOO Thumbnailer in Ubuntu 11.10 Oneiric Ocelot, use the commands below:
sudo add-apt-repository ppa:flimm/ooo-thumbnailer
sudo apt-get update
sudo apt-get install ooo-thumbnailer
Once installed, restart Nautilus:
nautilus -q
To download the source code, report a bug and so on, see the OOO Thumbnailer page on Launchpad.