Media Control Plug-in for Media Center - One of the great things about Windows Media Center is the all-in-one concept : you have all your pictures, music, videos and TV shows accessible from one remote control. Media Center customization is rather limited. For example, it was not possible to do a fast forward for "non-Microsoft" encoded videos. And what about MKV or AVI videos which have multiple audio and subtitle streams? How do you switch between them? What about external subtitle files? This is only a few of the things that this plug-in allows. Of course all these features are accessible using the remote control too! FFDshow is pre-configured in current releases to use this plug-in but you will need to change the subtitle renderer on the Config TAB of the Settings Application to use FFDshow also. Be sure a video is playing, and using ffdshow for decoding, (icons in the sytem tray) before accessing the configurations.
The above Plug-in is recommended by Shark007

MCERemotePlus - Toggle subtitles, audio streams, enable rewind and fast forward using the MCE remote for video files. This app is designed to work with ffdshow. It also supports toggling subtitles with DirectVobSub or ffdshow. This software is recommended by Shark007

NEW! MetaFox (recently updated to 0.95b) is a simple to use video file converter. The installer places a shortcut on your desktop. You drag n drop a file or even an entire folder onto the shortcut and it will convert the file(s) to MKV.
This tool is especially useful to Windows 7 users who have trouble with thumbnails or video playback.

DGSplit is an application designed to be a simple, small and easy to use file splitter that works on arbitrarily large files. You can use this tool to cut a sample sized piece from a very large video.

On the Help TAB of the 32bit Settings Application is a button to allow you to choose Windows Media Player Filetype Associations. Once you have used this button, you can Enqueue newly associated files to the Windows Media Player Playlist as depicted below. If for some reason this doesn't work for you, go back to the associations button, click No twice, consecutively, then select Yes. No reboot is required.

 
This will also work for audio files such as FLAC, APE or musepack.

Original Media Player Classic (with security updates) v6.4.9.1 rev 106 - Last Updated October 31st, 2009

UPDATED MPC Homecinema SVN releases - x86 and x64 versions are available here.
MPC Homecinema x86-rev1.3.1635  |-|-|-|-|-|-|  MPC Homecinema x64-rev1.3.1635

Reclock Directshow Filter - The purpose of ReClock is to help get rid of jerky playback of video material on a PC. It's a DirectShow filter which is loaded in place of the default directsound audio renderer.

DivFix++ is a program designed to repair broken AVI file streams by rebuilding the index part of a file. This is very useful tool when trying to preview movies that have no index part like some files currently downloaded from ed2k or bittorent networks.

TweakMC is a set of useful commands for Media Center Edition, adding additional flexibility to various areas of Media Center. Documentation and the Source Code is available as a reference to create additional custom TweakMC settings.

GraphEdit 32bit - DirectShow Tool v10.0 Build:090714 - This is Microsoft's DirectShow GraphEdit Tool designed with the latest Windows 7 support. If you are new to DirectShow, GraphEdit is a good way to become familiar with filter graphs and the DirectShow architecture.

GraphEdit x64 - DirectShow Tool v10.0 Build:090714 for x64 filters/codecs only
Same as the tool above except that this one is designed for 64bit Windows.

NEW! Media Foundation Topology Editor This tool is the equivalent of Graphedit listed above but is specifically built for working with WMF introduced in Windows 7 and will allow you to build a topology by adding various topology nodes like source, transform, and output nodes. ( No separate x64 version exists)

Speex Audio x86 || Speex Audio x64 - These releases will provide Speex audio support.