I'll skip the well-known sites because you're already aware of them.
  1. All Music
    allmusic.com How could I live without this one? Who else has recorded this song, and on what album? What are all of Jackson Browne's albums, in order, and which songs are on each one? And on and on . . . .
  2. Arts & Letters Daily
    aldaily.com Links to all kinds of good articles, book reviews, and opinion pieces. A classy site.
  3. The Browser
    thebrowser.com "Writing Worth Reading." Five or six articles a day that you might appreciate. Recommended recently by NYT columnist David Brooks.
  4. Chess Viewer
    chessviewer.com Sometimes you might want to watch a chess game in progress. Most of these games go fairly quickly, although some are just too fast.
  5. Headbutler
    headbutler.com Four days a week, cultural observer Jesse Kornbluth recommends a book, a CD, a movie, a TV show, or a product you'll want to know about and may want to buy. Also available as an e-mail, which I recommend.
  6. Metacritic
    metacritic.com Want to learn something about a movie before you decide to see it? This is the place!
  7. Previously TV
    previouslytv.com Not sure you understood everything in last night's episode? Want to see what other people thought of that show? This is the place.
  8. Slate
    slate.com A daily magazine online, and like everything else on this list, it's free. HIgh quality and great range.
  9. Mark Steyn
    SteynOnline.com If you don't happen to like his conservative views (and I do), you might want to read his wonderfully detailed weekly essays on classic American songs.
  10. Times of Israel
    timesofIsrael.com An online newspaper with excellent coverage of Israel and the Jewish world.