http://www.soundonsound.com/sos/mar14/articles/myths.htm - learned a few things from this one!
http://music.hyperreal.org/artists/brian_eno/oblique/oblique.html - Brian Eno's Oblique Strategies... if you don't know, now you know
http://musformation.com/category/recordingformation/ - great collection of recording content
http://education.lenardaudio.com/en/99_siteindex.html - heavy hitting site about all things audio
http://www.moozek.com/2008/09/10/20-intermediate-pro-tools-tips/ - great tips. I do all of these things.
http://www.sweetwater.com/sweetcare/mac-pc-optimization/ - should be known by all
http://www.youtube.com/show/pensadosplace - industry tv
http://garyewer.wordpress.com/ - one of the best writers on songwriting (next to jason blume)
http://music.tutsplus.com/tutorials/enhancing-the-kick-drum-with-sine-waves--audio-1401 - not the only place to learn this trick, but this trick must be known by all... simple to do, just have your bussing/gating game down
http://independentrecording.net/irn/resources/freqchart/main_display.htm - a powerful visuan aid (if used correctly)
http://www.digitalprosound.com/2002/03_mar/tutorials/mixing_excerpt1.htm - every site on the topic of audio has 'nuggets' peppered within the content sometimes... this one is no exception though it may come off as 'typical' eq-speak
http://quiztones.com/ - sharpen your most valuable "reference microphone" (your ears) with this
http://www.angelfire.com/fl4/moneychords/lesson.html - this kind of stuff comes in handy to aid in 'thinking out the box'
http://productionadvice.co.uk/how-to-avoid-over-compressing-your-mix/ - free meter that's useful for matching program material by rms values
http://ethanwiner.com/articles.html - a cool cat with cool articles
http://productionadvice.co.uk/using-eq/ - some numbers to understand. numbers help in mixing. they aren't end all, but there are definitely go-to numbers
http://wgo.signal11.org.uk/html/album-index.htm - what producer wouldn't want to know about the Beatles anomalies? enjoy.
http://www.musicradar.com/news/drums/100-greatest-drum-beats-of-all-time-204008 - i'll go into details about my 'lists' one day. this is a good one for producers
https://www.gearslutz.com/board/so-much-gear-so-little-time/556953-best-mixing-tip-youve-picked-up-gs.html - keywords are paramount. think in keywords. use the keywords. lookup discussions on them. this is how I learned what i learned and found these links. Again, not everything here is absolute, but should definitely be taken into consideration or entertained as a possible idea or solution to a problem.
http://www.soundonsound.com/ - pretty much one of the best sources on the topic of all things music and sound
https://www.gearslutz.com/board/5063002-post71.html - this is crucial. i never work without this method.
https://www.gearslutz.com/board/so-much-gear-so-little-time/556953-best-mixing-tip-youve-picked-up-gs.html - 7 pages of great tips :)
http://www.soundonsound.com/search?url=%2Fsearch&Section=8&Subject=63 - looking for something specific? search here first.
http://www.soundonsound.com/protools - literally stocked up
http://www.reddit.com/r/audioengineering/top/ - a wealth of information. be sure to check the other subreddits on the right side... this is where you'll find it all
http://www.homestudiocorner.com/8-microphone-mistakes/ - ive committed all of these and, from those mistakes, learned to never do it again.