I'd take Firefox over IE anyday, but that doesn't mean IE 7 is not an able browser. That also doesn't mean I use Firefox everywhere, because #1 on my list is Opera. Safari is not bad, but it's less "modular" than Microsoft's offering. Konqueror comes close after that.
Just visit the add-ons' page, it's high on the list and hard to miss. Grabbing songs off myspace is only a matter of one-liner commands if you have access to a Unix-compliant shell; you should've been worried a very long time ago :lol: