SMPlayer is a free media player for Windows and Linux with built-in codecs, which can also play Youtube videos, search and download subtitles, and includes other features like a thumbnail generator and audio and video filters.
One of the most interesting features of SMPlayer: it remembers the settings of all files you play. So you start to watch a movie but you have to leave... don't worry, when you open that movie again it will be resumed at the same point you left it, and with the same settings: audio track, subtitles, volume...
SMPlayer is a graphical user interface (GUI) for the award-winning MPlayer, which is capable of playing almost all known video and audio formats. But apart from providing access for the most common and useful options of MPlayer, SMPlayer adds other interesting features like the possibility to play Youtube videos or download subtitles.