I just discovered WiiMC (Wii Media Center), and promptly had to change my list, Five Essential Homebrew Applications, to remove MPlayer CE and replace it with WiiMC. MPlayer CE was a very good homebrew media player, but WiiMC is designed so nicely and looks so good that it rivals commercial products in a way Mplayer CE did not. It even offers streaming radio and - while it didn't work very well for me - video off the internet. If you're a fan of homebrew, you've really got to check this one out.

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What is the quality of streaming video? Have you tried “Orb” and could you offer a comparison? I tried Orb last night was was severely disappointed in the video quality. Thanks!
WiiMC is Capable of using shared folders from a PC & produces as is quality much like the PS3′s media centre, it’s a true media centre as opposed to the “orb” which converts on the fly all video media to the smaller and less impressive FLV format for streaming.
still it’s the first time I’ve actually started leaning on the Wii for all my multimedia needs.
Seriously, if you have a good wifi network set up and any amount of music/movies on a mac/pc at home, this is a must. The SMB network feature is phenomenal, and I can now just use the wii to play all my music/films wirelessly from my comp upstairs in the living room. It also runs rings around Mplayer CE in functionality and appearance – downloading it’s a no-brainer.