The HighLife

In no particular order...

http://www.HIGHLIFE.ME - can't leave Af & my musically charged blog out of this!
http://www.supernova.com - Indie music social network for fans and artists
http://www.interplanetarians.com - Music, Art, and everything in between.
http://www.flavorheard.com - Mixes, releases, parties, and ice.
http://www.thirtythirsty.com/ Thirty Minutes for Thirty Ears
http://www.dfarecords.com/radiomixes/ Some dope dance-able mixes - must check!
http://nugs.net/ Nugs.net - 'member this?
http://jamtopia.com
http://aurgasm.us/ 
http://topspinmedia.com/
http://www.shoutcast.com/
http://www.xlr8r.com/ Accellerating Music and Culture
http://wickedgoodscene.com/ - Check out the scene according to some of the raddest local Boston blokes infused with some badass kicks, streaming music, podcasts and a whole lot more than you bargained for!
http://www.muzu.tv/ Create a personalized music TV Channel with multiple video playlists in one player and embed on your site & social network of choice
http://www.iclips.net/ - Check out live sets of shows all over
http://www.be-at.tv/ - Live music events from different camera angles from around the world - this is awesome
http://www.spotify.com/en/
http://www.thesixtyone.com/ - like Digg for music
http://www.npr.org/music/ - NPR Music
http://www.pitchforkmedia.com
http://myrockstar.com
http://www.archive.org/index.php - An archive of hundreds of thousands of digital music recordings including live shows
http://music.for-robots.com/
http://www.darkaudio.co.uk/index.php - Some great LONG playlists of deep house music, various artists
http://www.deepershades.net/ - Lars Behrenroth's collection of weekly deep house internet radio shows, featuring a new guest DJ each week
http://www.flavorheard.com - Sam & Ben's growing collection of seriously danceable beats
http://www.fromthedeepend.com - Grooveshark's music blog
http://thehype.fm/ - A sleek music blog radio site
http://hypem.com/ - An aggregated list of music from an extensive array of music blogs
http://elbo.ws/
http://www.rocksellout.com/
http://www.paperbuddha.com/
http://prettymuchamazing.com/
http://www.dctobc.com/
http://electrorash.com/
http://www.spooonful.com
http://www.thenextbigsound.com - sign up to create a 'record label' and 'sign' artists you like. Check out the map to see top 'signed' artists by state
http://boramusic.com/default.htm
http://mog.com
http://themusic.fm
http://www.whatisgoodmusic.com
http://blackcabsessions.com/ - One song. One take. One cab.
http://www.pampelmoose.com
http://www.loud.com/ - Hip Hop related
http://www.thedailykush.com/
http://www.odeo.com/categories/34-Music
http://www.beyondthegroove.com/
http://blogfreshradio.com/
http://musebin.com/
http://www.chromewaves.net/

Mashups
http://www.mashup-charts.com/ - Exactly what you think it is
http://maxmashups.com/
http://www.spinjunkies.com/spinjunkies_home.htm (just great mashups)
http://www.mashuptown.com/
http://djearworm.com/
http://thru-you.com/ - YouTube video mashups by Kutiman - Incredible stuff!

Games
http://loudcrowd.com/
http://www.audio-surf.com/ - Ride Your Music!

Music Blogs & Magazine Sites
http://www.stateofmindmusic.com/
http://www.okayplayer.com/
http://deathelectro.com/
http://stereogum.com/
http://undergroundboston.net/
http://www.bostonmusicspotlight.com/
http://music.ology.com/
http://www.babelgum.com/index.php?category=music
http://www.iclips.net/
http://thebutterroom.com/ - "Built to spread live music goodness"
http://thecurbcrawlers.com/blog/
http://kennygrant.ca/ - House Music Blog
http://mikevee.com/
http://www.popsense.com/search/label/music
http://standingroomtickets.com/
http://www.laundromatinee.com/
http://electrorash.com/ - Indie / electro / techno / disco
http://www.mtv.com/music/
http://current.com/topics/32966072/music/default/0.htm
http://youfunkinloveit.blogspot.com/
http://www.ohhcrapp.net/

Online Radios & Stream-ers & Music Search Engines
http://www.onlineradiostations.com - An aggregation of streaming radio stations
www.wers.org - Commercial-free music for the independent mind - Emerson College, Boston
http://www.muxtape.com
http://concerts.wolfgangsvault.com Free streaming live music, Live concert recordings, Live music downloads, Classic rock concerts
http://www.playlist.com/
http://soundcloud.com/
http://www.stumbleaudio.com/
http://www.onellama.com - Listen in on any online radio show around the world - it's hit or miss
http://www.pandora.com
http://last.fm
http://www.slacker.com
http://www.musicovery.com - Choose your mood and it will choose your music
http://www.liveplasma.com/ - Similar to Musicovery
http://www.meemix.com
http://www.finetune.com
http://www.lala.com
http://www.plistube.com - Enter an artist and this site will auto-create a YouTube video playlist
http://www.imeem.com
http://free.napster.com
http://www.seeqpod.com
http://www.deezer.com
http://www.songza.com - Music search engine
http://mixturtle.com/ - Another music search engine
http://www.grooveshark.com
http://www.skreemr.com/
http://www.podnova.com/ - Lists subscription sites
http://mp3realm.org/ - Searches for mp3's
http://www.music-map.com/sts9.html - Tag cloud search
http://www.radioblogclub.com/
http://www.lala.com/
http://www.thefreshpage.com
http://www.stompy.com


Music-Related Event & Ticketing Sites
http://www.fusicology.com
http://www.jambase.com
http://www.crowdfire.net/
http://www.bandsintown.com
http://www.tourfilter.com
http://www.womapp.com
http://www.wanttickets.com
http://www.clubzone.com
http://gruvr.com/
http://www.groupee.com/

Music Labels
http://www.sidehatchentertainment.com/ - Boston Based label / management company with some solid rockers
http://maddecent.com/blog/ - Diplo's Record Label
http://1320records.com - home to the likes of Sound Tribe Sector 9 (STS9), Pnuma Trio, Eliot Lipp and others
http://www.myspace.com/edbangerrecords - Ed Banger Records - home to legends such as Justice, Mr Oizo, Uffie, Feadz, & others
http://www.myspace.com/lightsoverlosangeles - Lights Over LA
http://d4dirtyrecords.com/ - An Underground Electro/Progressive Record Label
http://www.om-records.com/

Social Networks/Resources/Services
http://www.songbird.com - A music browser
http://the.echonest.com/
http://fairtilizer.com/ - A "do-it-yourself music club"
http://jamsbio.com/
http://www.bossalive.com
http://www.thesixtyone.com/
http://www.artst.com/galleries#music-0-newest - Pharell's artist hub - music section
http://blip.fm/ - Create your own music station
http://www.dvdvideosoft.com/ - Rip YouTube videos and convert to MP3s
http://vixy.net/ - (Same as above)
http://www.traxsource.com/
https://www.beatport.com

Honorable Mentions
http://www.blogotheque.net/
http://www.ericstromsdailysong.com - A song each day from Eric Strom
http://mashable.com/tag/music/ - Web news tagged with "music"
http://www.buzzdash.com/polls/entertainment/music/ - Surveys on bands, songs, albums & events


Festivals
http://www.burningman.com/ - Burning Man
http://www.bonaroo.com - Bonaroo
http://www.coachella.com
http://www.ultramusicfestival.com/ - Ultra Music Festival
http://www.sxsw.com/music - South by South West music section
http://www.allgoodfestival.com/
http://www.hardfest.com/ Hard Haunted Mansion in L.A. (peep http://www.youtube.com/watch?v=y7tI1E6kp0o for a taste)