Among Canon, Epson, HP, and Lexmark, there are seven USB ink jet printers. There are hardly any lasers and no multifunction peripherals. Mass storage needs more breadth. The 100MB Iomega Zip Drive has a USB version, but not the more desirable Zip 250 or the 1GB and 2GB Iomega Jaz Drives. With those, I could swap one device easily among several desktops and portables.
Audio benefits are uncertain.
USB promises purer sound, because interference inside the PC affects analog but not digital signals. UPS proves a pleasant surprise. Nobody uses uninterruptible power supply auto-shutdown features on desktops, because they don't want to give up serial ports for the control cables.