Creative Synth is a labor of love of Darwin Grosse and a small but dedicated group of writer/musicians. It focuses on modular hardware and software, and getting the most out of synthesizers.
There are tutorials on many of the major synth platforms, along with opinion pieces and columns.
There is an excellent Reaktor tutorial, along with an overview of Reaktor 3. There is a column on Ableton Live. Other interesting sections cover synth building with Max and Buzz, and programming Absynth.