Since 3.5 (planned for Precise), LO has an import filter for MS Visio files (.VSD) . Those files currently have no default association with any application, so it would be a major usability improvement to have them open in LO by default.
Filing against LO because I'm not sure what package controls default file associations.
DistroRelease: Ubuntu 12.04
Package: libreoffice (not installed)
ProcVersionSignature: Ubuntu 3.2.0-12.21-generic 3.2.2
Uname: Linux 3.2.0-12-generic x86_64
Date: Sat Feb 4 17:46:40 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110921.2)
UpgradeStatus: Upgraded to precise on 2012-01-14 (21 days ago)