[X] Suprnova.org - The torrent index giant is dead and gone. [Read the Unofficial SuprNova.org Closure FAQ for details]
[X] TorrentBits - Dead and gone.
[X] TV Torrents - I thought it was gone, but it's just the .net redirect; you should now be visiting tvtorrents.tv.
[X] LokiTorrent - Alive for now; trying to raise funds for their own legal defense.
The Unofficial SuprNova.org Closure FAQ has a list of (currently, at least) running Torrent index sites here.
For more information on the shutdowns, read The Gadget Lounge and their hopeful look to the Torrent future with eXeem.