First, it seems you read a bit, and you have done some similar stuff before, and that's a good thing, but be sure to read updated info, since the wii scene is rapidly changing
you could check the link in my signature for a Complete softmod guide, but this is not a do this then that guide... this is one where you learn a bit while you do it, and why
It's constantly updated as a team effort.
And also, check out wiibrew.org for some hints on what your wii can do
If you partition your disc correctly, it can contain anything you want, and there's homebrew for things like playing movies, music, viewing pictures, streaming video from ftp, or over smb. Just keep in mind that the wii is a bit limited, since there's no HD capabillities.