These come in very handy for playing different formats of multimedia, conversion of many different formats such as DVD, AVI, MOV, WMV, and damn near anything else you can imagine.

These are not only my personal recommendations after years of trial and error, but I’ve also included recommendations by many others. This is an excellent list and I intend on updating it with newer items later. Please feel free to comment if you have any additions to the list.

See the entire article for links and descriptions.

* = My personal recommendation.

AutoGK* - DivX / XviD backup utility. Support for DVD, MPEG2 (such as DVB captures and transport streams), MPEG1 sources, along with AVI/DV sources.

DVDShrink* - Backup your DVD disks. You can use this software in conjunction with DVD burning software of your choice to make a backup copy of any DVD or create a DVD image.

GOMPlayer* - GOM Player supports most popular codecs (AVI, DAT, MPEG, DivX plus many more) with its own embedded codec system that you won’t have to look for appropriate codecs every time. It also supports FLV files (for example: saved YouTube videos) and does the best job of any FLV player I’ve found. It’s hard to find a good FLV player, because most have lots of issues and will not allow you to maximize/resize the video.

VirtualDub* - Video capture/processing utility for 32-bit Windows platforms (95/98/ME/NT4/2000/XP). It lacks the editing power of a general-purpose editor such as Adobe Premiere, but is streamlined for fast linear operations over video. It has batch-processing capabilities for processing large numbers of files and can be extended with third-party video filters. VirtualDub is mainly geared toward processing AVI files, although it can read (not write) MPEG-1 and also handle sets of BMP images.

VirtualDubMod* - Based on the famous video editing software VirtualDub by Avery Lee. Born as a unification of several existing modifications, a lot of new features have been added, including support for the matroska container format.

VLC Player* - Highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, …) as well as DVDs, VCDs, and various streaming protocols. It can also be used as a server to stream in unicast or multicast in IPv4 or IPv6 on a high-bandwidth network.

Daemon Tools* - Virtual CD/DVD-ROM-EMULATOR. Mount your images as a drive (one use would be to watch a DVD from a backup image).

VOB2MPG - VOB2MPG goes through a whole DVD VIDEO_TS folder and joins up the various vobsets to produce mpgs for the different titles.

Handbrake - HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded DVD to MPEG-4 converter, available for MacOS X, Linux and Windows.

iSquint - iPod video conversion app for Mac OS X.

Any Video Converter - Convert video files from various formats. Video formats including DivX, XviD, MOV, rm, rmvb, MPEG, VOB, DVD, WMV, AVI to MPEG-4 movie format for iPod/PSP or other portable video device, MP4 player or smart phone. It also supports any user defined video file formats as the output.

Videora Converter - A set of programs, each designed to convert regular PC video files into a format tailored to your favorite video-playing handheld device. The Videora program list includes iPod Video Converter (for 5th gen iPods), iPod classic Video Converter (for 6th gen classic iPods), iPod nano Video Converter (for 3rd gen iPod nanos), iPod touch Video Converter, iPhone Video Converter, Videora Apple TV Converter, PSP Video 9, Videora Xbox360 Converter, Videora TiVo Converter, and Videora PMP Converter.

SMPlayer - Multimedia player. It uses MPlayer as its engine, so it’s able to play the most known video & audio formats without the need of external codecs. SMPlayer is available for Windows and Linux.

DVDFab HD Decrypter - DVDFab HD Decrypter is a simple version of DVDFab Platinum. It copies entire DVD movie to hard disk, and removes all the protections (CSS, RC, RCE, APS, UOPs and Sony ARccOS) while copying. It also comes with full HD-DVD and Blu-Ray support (Removes AACS).

Media Coder - Batch convert audio and video compression formats with the open source Media Coder for Windows, which works with a long laundry lists of formats, including MP3, Ogg Vorbis, AAC, AAC+, AAC+V2, MusePack, WMA, RealAudio, AVI, MPEG/VOB, Matroska, MP4, RealMedia, ASF/WMV, Quicktime, and OGM, to name a few.

SUPER - Universal Player Encoder & Renderer. A GUI to ffmpeg, MEncoder, mplayer, x264, mppenc, ffmpeg2theora & the theora/vorbis RealProducer plugIn.

DVD Flick - DVD Authoring tool. It can take a number of video files stored on your computer and turn them into a DVD that will play back on your DVD player, Media Center or Home Cinema Set. You can add additional custom audio tracks as well as subtitles of your choice.

RipIt4Me - RipIt4Me is a freeware utility that helps you backup your copy protected DVDs. Recently released DVDs are now very often equipped with stronger copy protections - such as ARccOS and RipGuard DVD. Programs like DVD Shrink or DVD Decrypter cannot handle these types of discs. RipIt4Me is fully automated and the wizard will guide you through all the necessary steps involved.

Zune Software Hack - This is a mod made so that the Zune program will support more types of video, audio, and image extensions.

Encode360 - An application which will convert virtually any video format to high quality WMV’s which can be played by the X-Box 360, the Microsoft Zune device, or anything else that likes WMV format.

Movie DVD Maker - Supports converting almost all formats of video files to make DVD. So you can convert AVI to DVD, MPEG to DVD, etc.

All to AVI - Tool to convert especially ogm and mkv files to avi, with subtitle and audio track selection, video resizing, bitrate selection and codec selection. It is centered around mencoder, with a commandline tool as well as a GUI for Windows.

MeGUI - GUI based ISO MPEG-4 solution. It suports MPEG-4 ASP (XviD & libavcodec MPEG-4) using mencoder, MPEG-4 AVC (x264) using x264 CLI or mencoder, (HE)AAC audio using BeSweet & Nero AAC encoder and MP4 muxing using mp4box.

If you can “afford” it, I recommend Adobe Premiere for an excellent non-linear video editing package.

Resources:
VideoHelp.com
Doom9.org Guides