This is actually the only reason we're still running a ColdFusion server. About once every 6 months I look at the options out there, but until the FSF gets the momentum going behind GNU PDF (http://www.fsf.org/campaigns/priority-projects/), I think CFM'll still rule the roost.
We also rely on pieces like OOONinja's ODF converter to cope with .docx files (http://katana.oooninja.com/w/odf-converter-integrator).