A new Synth was released by NuDSP. The Mod271 (MODE-271) is a virtual modular DSP playground with unified MIDI/AUDIO support. According to its creator:"Mod271 is supposed to exist somewhere in between Reaktor and Reason".

Features:  

• MIDI and ASIO support
• built with portability in mind, a mac/linux version shouldn’t be terribly difficult.
• everything is a full audio-rate signal which means you can do DSP type stuff to say a MIDI stream.
• there is a VSTi version in the works but it is still pretty unusable in a general case.
• every node can be automated with unlimited control points and automation takes place right in the 3D environment.
• nodes can influence any amount of other nodes or switched into a singular state.
• all signals are drawn at audio rate and with full hardware acceleration, although this can be disabled.
• the entire environment is rendered in 3D.
• radial and linear influence modes are supported for every node.
• all envelopes and motion are completely sample accurate, meaning you can make an oscillator out of an envelope.
• over 25 node types, of course this is going to grow.
• Python node type that will allow easy extensions.

The entire interface is depicted in 3D. YOu can also zoom in and out with the mouse wheel.  Zooming in on a node will give you more accurate control over its locating,On the other hand by zooming out you can get a general overview of the connections.