Hi SGK,
Drives is one aspect, in addition to USB 2.0 ports, there is also on the rear an esata hook up and inside the system everything needed to install a drive. We have had up to a internal drive plus four usb powered drives connected and powered during startup. Keep in mind different drives use different amounts of power, but the end user shouldn't have difficulties powering three or more drives off the USB ports. As to the number of files, where the BDP-1 begins to slow down at around 30k songs (some users may experience different results depending on file type) the BDP-2 does not.
Cheers,
Chris