ALLPlayer is a powerful media player that as the name suggests, can play just about any format.
Similar to VLC media player, ALLPlayer is ideal for playing stubborn video files that won't play in your usual video player. It supports subtitles and plays just about anything and if it can't play a file, it will try to download the appropriate codec from the ALLPlayer website. If you need subtitles for a film, it will even try and download those as well although this function is very hit and miss. An unusual subtitle feature is an automatic voice recognition system that actually reads the subtitles for those who are visually impaired although again, it's not very accurate.
However, one thing to be aware of is that ALLPlayer is based on DirectX which is notorious for being a backdoor for trojans and other malware. DirectX has been much improved and tightened-up since the bad old days though and this shouldn't be an overriding concern if you're thinking of using ALLPlayer.
There are tons of other features in ALLPlayer including an attractive iTunes style Coverflow browser, support for Dolby, and it even previews incomplete AVI files such as those that are downloading. The interface isn't as polished as VLC media player's version 2 release but this is a relatively minor drawback to a solid media player.
ALLPlayer is an excellent multi-format media player that's packed with features.