I scan about a dozen book blogs each day. Several are written by major newspapers. I highly recommend Jacket Copy from the Los Angeles Times. I've found it to be the most readable and entertaining of the blogs produced by newspapers.
On the opposite end of the scale is Paper Cuts from The New York Times. I've never warmed to this blog, which seems rather staid and has a penchant for extended riffs on music, bands, songs, etc. recommended by authors.
There's also Short Stack from The Washington Post, The Book Room from The Chicago Sun-Times and Between the Covers from The Miami Herald.
I highly recommend The Book Bench from The New Yorker. It bounces between chatty tidbits and more extended pieces. For example, Ligaya Mishan has been reading and blogging on Roberto Bolano's 2666.