Does anyone know of any "Must have" song lists out there on the web?
That's a very tough one to fill. In order to cover everyone's musical tastes, the list would have to be enormous. I think a better way of going about it could be to start with a genre, then go from there.

Even then, if you asked me which "gunge" rock songs to listen to, I'd probably have a hard time formulating a list. I'd probably end up giving you about 30 songs
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Matt