There are many interesting points made by all of you. I must first ask why a module? In working with many film composers and doing a few "B" films myself, I have learned that what creates
realism in orchestration is "expression".
Why do you think static samples require
5 CD ROMs? It's because each expression requires a new sample.
If you have a very powerful synth engine that can add expression to high quality samples in "real time" with ribbons and breath controllers and after touch and release control , etc. (I think I made the point)., then you begin to be a "synthesist" rather than one who plays pretty sample from a keyboard. Therein lies the beauty and passion of traditional instruments.

Now racks are great and I suggest them when live performances demand large amounts of polyphony.

One such rack was not mentioned and it has the best dynamic range and 64 notes of polyphony expandable to 128.
This is the PC2R from Kurzweil. the list price is about $1,000.00 US. the Orchestra expansion board will be released very soon and the expression
for real time controllers is already built in.

I use a K2600SX (88 Key w/ sampler) for 99% of all I do. It has 88 real time controllers, It can resample it's self with
FX and has a built in sequencer.

So if I'm in the studio or on the road,
I can write and Play by resampling,
I can have unlimited polyphony and unlimited effects without losing dynamics or clipping because there is 256db of headroom.

My 2 cents. I have had all brands and endorsements from most. Kurzweil is the one product that consistently gets me work and a paycheck