The problem is that I don't know of any software
synthesizer that is:
1. good enough for decent music production;
2. easy to use by non-experts (this is a direct stab at CSound, or
better at its lack of a decent GUI, of a standard instrument exchange
file format and of a decent, centalized library of presets)
3. free software.
have you checked out supercollider? its somewhat dubious on point 2 I guess.
dave