I generally use only free synths, but I've had the chance to play with this instrument by Tone2 (and their previous one, Rayblaster) as I've done some sound design for them (some of my patches are part of the factory bank and probably more will be part of future expansions). I mention it here because, among other things (it's pretty versatile), it's great for ambient/mid-era Berlin School stuff. The synth is here, if you want to try it http://www.tone2.com/html/nemesis_sy...r__vst_au.html

This is a track from my next album, which will be made solely with Nemesis (internal arpeggiator, no external fx except during the mastering phase), so you can have an idea of what it can do

http://www.macvibes.com/SOUNDS/SUSPE...f_BIOnighT.mp3