Ableton Forum

osxaudio.com
KVR
Unicornation
NI user forums
Harmony Central

Mostly here though, the others are slow, and if you thing the flaming is pointless and long winded here, try reading any major announcement on KVR!

Electro-Music, Gearslutz, Native Instrument, Propellerhead, Home Recording, IDM, Digi User, Music Radar, KVR, SectionZ and of course this one.

dogs on acid
kvr
uad
native instruments