Q3: So which is faster, a USB peripheral or a serial/parallel/SCSI/1394/etc. one?
A3: This depends on what the peripheral is and how it's made. For example, a USB keyboard won't let you type any faster than a normal PS/2 keyboard because your typing speed is limited by how fast your fingers can hit the keys, not by the speed of the keyboard's connection to the PC. Similarly, devices like printers and scanners may be able to run faster on USB than they can with a standard parallel connection, but only if the print head or scan engine can keep up with USB's higher data rate, which is not necessarily the case. On the other hand, USB makes possible peripherals that were impractical with earlier connections, such as video cameras and ADSL and satellite modems.
I have a Cannon S630 running USB and it not only runs faster the USB cable was cheaper than the parallel cable!