trident, it depends on which softsynths you plan on using. Softsynths like Kontakt, GigaStudio, Halion, etc. are many orders of magnitude superior to any hardware based (keyboards or modules) samplers on the market today. This also assumes you acquire very high quality virtual (sampled) accoustic instrumets (Bardstown Bosendorfer Piano, VSL Saxophones, Scarbee Base, etc. In addition, you also need to use very high quality effects (reverb, chorus, delay), for example, Pantheon Lexicon, Sonitus and others.

So if you get top of the line softsynth and assoiciated software you will greatly exceed any hardware based solutions. You can check this by listening to the various demos available on the internet, e.g., search Bardstown...., etc.

I hope this gives some useful information.