Hello Mark!
All our sound sets work for standard and extended versions. The sound sets included with Sibelius are for the Special Edition and the Special Edition PLUS. As Bogdan has written, there are more sound sets available from our homepage after registering our products. Just take a look at the list he posted.
Some collections like the Konzerthaus organ or the Vienna Imperial don't need special sound sets.
Yes, all of our software is Windows 7 64-bit compatible. I haven't heard of any problems with the M-Audio Delta yet.
As far as I know the Sibelius internal reverb does not work with our software, but you can use reverb plugins like the Convolution reverb from our Vienna Suite. You can get a free demo version here:
http://vsl.co.at/en/211/497/1686/454/1673/115.htm
You will need a Vienna Key (or an eLicenser dongle from Steinberg) to use it.
Best regards,
Andi
Vienna Symphonic Library