Acoustic Noise - Cool tools to help you with your room acoustics.
 Berklee Shares - Berklee school of music is giving some free lessons!
 Kvr-VST - Database of every single VST instrument there is!
 Plogue Bidule - realtime modular creation studio
 Paia - user assembled kits for innovative electronic products


Audio news, forums, tutorials, resources...

 SAE.nl - School of Audio Engineering
 Audiofil.net - Croatian HiFi news and busy audio forum!
 Audio Textbook - kinda everything you need to know about sound
 Audio World - who wants to know more?
 Audio Ideas - audio and home theater news
 Studio Forums - have a question?
 ReasonStation - Reson Forums, free downloads and more
 eCoustics - consumer electronics information
 Computer Music - MIDI tutorials
 This day in music - what happened in music history today
 Obsolete - 120 years of electronic instruments

Software, plugins, misc progs...

 Nomad Factory - Nice tube plugins for your mixing pleasures.
 Voxengo - Old school solid sounding plugins.
 dB PowerAmp - Free audio converter, most of known sound formats supported!
 AnalogX - cool free plugins
 Antarestech - famous AutoTune developer
 Virtual Audio Cable - connect programs internally!
 Vellocet soft - oh what joy, control midi via joystick!
 CARA - Don't like your room acoustic? Let computer aid you!
 kxproject - take control over your ASIO drivers
 Native Instruments - makers of awesome virtual instruments [VST's]

Hardware
 MOTU - They have some cool audio hardware which is getting cheaper!

Samples, music, loops...

 A home - nice site with links to loads of samples
 DJ[BB]'s Breakbeat Paradise - Break the beat samples, very groovy!
 FlareSound - jazzy and deep house and downtempo webcasts
 Realprosounds - free high quality grand piano for NI Kontakt here!
 all out of Reason - many links to refills, soundfonts, samples, tutorials...
 Pianographique - awesome designed page for playing with sound and graphic

Other...
 Sci-Fi - Read some sci-fi books here! (not hi-fi)

 7volts - modifications to your pet computer
 Wood Contour - wooden mice anyone?