Urs Heckmann (known as U-he) is one of the best VSTi developers around at the moment. He wrote some free software including Triple Cheese that you may have tried, and more recently the commercial VSTi Zebra. His free and pay stuff is at http://www.u-he.com/.  He's currently building a new synth concept called "Berlin Modular", which will be a full modular synth on your PC or Mac, and will have individual modules just like a hardware modular system. Everything can be routed to everything. The promise is of a piece of software that will rival the very best original analogue hardware but with much more precision and control. And this guy knows how to programme a synth with an analogue-style sound like few others.

Berlin Modular won't be ready until Q2 2010 or later, but he has just released a new synth based on his work so far. It's basically a small part of what the full Berlin Modular system will be. It sounds amazing, and is fairly cheap at 69euros, 10euros cheaper with the discount code "spaghetti" when you check out (only for first 333 purchases). The demo is available at http://www.acesynth.com/ and is unrestricted, although a short sound is emitted every minute until you pay for and register it.

If you like analogue sounds you should give it a try. The only problem is that it's a real CPU hog: you need at least a dual core processor, and even then you will hit 100% CPU with some of the more complex patches. At least download it and try some of the patches though, there are some realy impressive sounds and the synth itself isn't too complicated to use.

Charles