patches.zone Great lessons for Ableton live and great sample downloads too.
Silver Wilkinson, Transcribed The Bibio album 'Silver Wilkinson' transcribed. One of my favourite albums and expertly transcribed.
The Joanna Newsom Transcription Project Some great indie and folk sheet music.
Josh Penslar's Electric Mixtape A couple of pieces of sheet music, including a fantastic transcription of Sufjan Steven's 'Come On! Feel The Illinoise!'
Disaster, please! Disasterpeace, the artist behind the soundtracks for Fez, It Follows and Hyper Light Drifter has a fantastic blog where he talks pretty in-depth about the creation of his music.
CKendrickMusic More of a jazz site but an insane amount of really accurate transcriptions. Staggering.
Know The Score Nine Inch Nails sheet music
Zeroes and Ones Really great in-depth tutorials and some cool modular synth stuff too.
Andy Othling Ambient guitarist with great lessons on using delay, reverb and other effects.
Andrew Huang Music channel with lots of creative ideas for song creation.
TAL- Togu Audio Line Great sounding plugins, mostly free.
ValhallaDSP Fantastic sounding, versatile reverbs.
SoundHack Free plugins that can get some really out-there sounds.
Boscomac Free instruments and effects for NI Reaktor. Amazing sounds, creative and great interfaces.