Recently, an article was published on Ynet about jogli.com, a site that tries to bring together various websites that contain music resources (music videos on sites like Youtube, lyrics from sites like lyricwiki.org and so on) into a single search engine resource. So far, I'm loving it. Give it a try.
I interject with imeem, which seems pretty good for obscurer stuff. Don't know if it's already part of Roman's conglomerate site.
Hm. I know some more, but is it an "illegal" link when dowmloading is, with some technical knowledge possible, but obviously not the intent of the site? (I mean, purely technically, recording the songs from the sites posted so far is possible too.) I'm asking this without a wink, I'd really like to know.