Freemake Video Converter
Name: Freemake Video Converter
Description: (taken from website) Convert video free to AVI, MP4, WMV, MKV, SWF, 3GP, DVD, MPEG, MP3, iPod, iPhone, PSP, Android, rip & burn DVD, convert online videos directly from 40+ sites, burn Blu-ray, and upload to YouTube with our free video converter!
Notes: I know this has been mentioned at least once here, but never in proper request apps format. It seems to require .NET 4.0, so this is a longshot to become official even after the .NET apps section goes live on this site. Still, it's a very handy tool, and I'm sure would have many users even as an unofficial app.