Allmusic: The AMG editorial staff, along with hundreds of expert contributors (all music fanatics in their own right), has made allmusic “the most comprehensive music reference source on the planet.”  Here you will find reviews of all different genres of music, along with details about artists, albums, and more.

The AV Club–Music: This entertainment newspaper and website published by The Onion features reviews of new films, music, television, books, games and DVDs, as well as interviews and other regular offerings examining both new and classic media and other elements of pop culture. Unlike its parent publication, The A.V. Club is not satirical, though much of its content maintains a similarly humorous tone.

Commonsense Media–Music Reviews: An organization that is “dedicated to improving the lives of kids and families by providing the trustworthy information, education, and independent voice they need to thrive in a world of media and technology” here provides reviews of children’s music albums, and rates them according to age level and appropriate content.

Dusted Magazine: Here you will find critical, intelligent reviews of new music and weekly college radio charts.

The Guardian–Album Reviews: A differing perspective on music releases from the British newspaper.

Metacritic–Music: Here you will find information on new releases, tours, and music news.

New York Times Music Section: Reviews, articles and music news from the New York Times.
NPR–Music: Here you will find not only music news and reviews, but podcasts, a song a of the day, and more.
1000 Recordings to Hear Before You Die: The site title says it all!  Award-winning music journalist Tom Moon has been searching out peak musical experiences from all genres and every corner of the earth. His book, 1000 Recordings To Hear Before You Die, was published by Workman Publishing in August 2008.  His website features a podcast, blog, and his list of recordings, which is browsable by genre, artist, and title.
Pitchfork: This music site is devoted to music criticism and commentary, music news, and artist interviews.
PopMatters–Music: PopMatters is an international magazine of cultural criticism providing readers with sharp, entertaining writing on a wide range of topics in pop culture, offering a refuge from the usual hype and gossip. In the music section, you will find articles and reviews of new music releases in a variety of genres.
Rolling Stone–Album Reviews: The pop culture magazine includes reviews of new music releases.