Video Video Programs
DivX
DivX
Version: 5.2.1 Date: Sep 3, 2004
Description: This codec (which works in the DivX Player, Microsoft's Media Player, and probably some others) handles the Divx video format (which is an MPEG-4 based format).
DVD Decrypter
DVD Decrypter
Version: 3.2.2.0 Date: Apr 25, 2004
Description: A free DVD "ripper". In "File Mode" DVD Decrypter easily rips the whole DVD. The resulting files are best played in a real DVD player (like WinDVD), since you'll have lots of VOB and IFO files (which are not easily played in, say, mplayer). You can also rip in "IFO Mode", which (like DVD Shrink) allows you to pick which audio tracks and subtitles (and even which "extras"!) you want to rip. Like Smart Ripper, you can set DVD Decrypter to rip the movie to a single (large!) VOB (Tools -> Settings -> IFO Mode -> Options -> File Splitting). Doom9 has a nice guide to DVD Decrypter.
DVD Shrink
DVD Shrink
Version: 3.1.7.6 Date: Apr 9, 2004
Description: A free DVD "ripper", with the added ability to compress a DVD! If you set your "target DVD" size large enough, DVD Shrink won't automatically try to compress the DVD. DVD Shrink allows you to decide which parts of the DVD (like audio tracks, subtitles, etc.) that you want to keep. Doom9 has a nice guide to DVD Shrink, and so does MrBass.
Media Player Classic
Media Player Classic
Version: 6.4.8.2 Date: Mar 27, 2004
Description: An open-source multi-format player that seems to have stolen its name and icon from an early version of Microsoft's Media Player (now officially known as Windows Media Player).
mplayer
mplayer
Version: mar 26, 2004 Date: Mar 26, 2004
Description: This is a Windows build of mplayer, an extremely popular, open-source, multi-format player. Since the basic mplayer is command-line only, this build is bundled with mplayer launcher to give some semblance of a modern-day tool. It's not pretty to look at, but is said to be able to play anything on anything.
Net Transport
Net Transport
Version: 1.82.237 Date: Feb 20, 2004
Description: With more and more media/content providers offering media "streams", it's not surprising that more and more programs are offering ways to save those streams! Net Transport is even better than Streambox VCR (below), and it's also free!
QuickTime
QuickTime
Version: 7.1.5.120 Date: Feb 16, 2007
Description: Apple's audio/video player can play just about any of the "open" standards, as well as Apple's proprietary QuickTime format, of course.
RealPlayer
RealPlayer
Version: 10.5 (build 6.0.12.1056) Date: 2004
Description: Real can't decide on the name of their Player (Player -> Jukebox -> One -> Player), but it's still a decent audio/video player.
Smart Ripper
Smart Ripper
Version: 2.41 Date: Dec 15, 2001
Description: This tool hasn't been update in a while, and doesn't seem to be supported anymore (there isn't a real homepage). However, Doom9 has a nice guide to Smart Ripper, and they mention that you should install an ASPI driver (but use this newer one), which seems like a good idea. Anyway, for an old, unsupported program, this does a great job! Smart Ripper even has a quick "Movie Only" rip mode. You can also tweak the settings so you don't end up with multiple 1GB VOBs, instead getting a single (large!) movie VOB.
Streambox VCR
Streambox VCR
Version: 1.0 Beta 3.1 Date: Jun 6, 2000
Description: Once upon a time, Streambox Inc. created a utility that saved streaming video to a local file. Real.com didn't like this, and sued Streambox, which cancelled this program. It might be illegal to use this program in the United States. Still, it is available at Streamgen and After Dawn. Read this excellent unofficial tutorial. Since Streambox is no longer under active development, it's fallen a bit behind. Try Net Transport (above).
vlc
vlc
Version: 0.7.1.0 Date: Mar 2, 2004
Description: Plays a variety of video and audio formats, including streaming files and ripped DVDs (haven't tried that yet, though).
WinDVD
WinDVD
Version: 4.1.11.33 Date: Aug 6, 2002
Description: Nice DVD player. There's a newer version, but this is the one I'm using (it came with my computer).
MediaPlayer
Windows Media Player
Version: 11.0.5721.5145 Date: Oct 18, 2006
Description: Plays a variety of video and audio formats, but I hate the UI. Try iTunes or QuickTime!

Xvid Codec
Version: 1.0.3-20122004 Date: Dec 20, 2004
Description: This is Koepi's binary codec for the XviD format. You can find another binary codec at Nic's XviD page.

The information above represents my experience with a certain version of each piece of software. I have no vested interest in any of these programs, and only provide this info as a guide (your experience and preferences may vary greatly!).

The version number listed is the latest version I have tried. To download the latest version, click on the name or the icon of the program, which should take you to the program's homepage, or to a software archive site.