Quicktime + Perian = Delicious

Picture 5 Picture 6 Sure VLC works great, but the UI of Quicktime is superior. You can seek in the video and see the time remaining without exiting the full screen. Perian lets you watch all those videos on the Internet and Bittorrent without any hassles. Perian enables QuickTime® application support for additional media types including:
  • AVI and FLV
  • 3ivX, DivX, Flash Screen Video, MS-MPEG4, Sorenson H.263, Truemotion VP6, and Xvid
  • AVI support for: AAC, AC3 Audio, H.264, MPEG4, and VBR MP3