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.