1. Run a separate disk for all your samples, leaving the main disk for Windows and programs.(Dual booting systems will have no effect on performance)
2. 32 bit will be fine for now
3. Interface speeds; Firewire = 400, USB 2 = 480, Firewire 2 = 800, (Unfortunately not properly supported by Windows, so you may as well stick with standard Firewire) Gigabit Ethernet = 1000
4. Motherboards are also available with an E-SATA socket (External SATA) which will give the same performance as an internal drive
5. Best value Orchestra; Garritan GPO
6. Best GM set; Colossus (But look out for the soon to be released Garritan GM set)
7. You will find that most people who have a Genuine B3 and a computer, use Native Instruments B4 VST (As close as you can get to the real thing, so close in fact that unless you are a aficionado of the B3, you will not be able to tell the difference)
8. As to VST being specialist, this has not been the case since 2000 (Wersi allows you to load and use them in a normal keyboard, with Lionstracs bringing out a new board that can also use them, a few years later)
Enjoy whatever you play

Bill