Thank you guys for your responses.

Gary, to answer your question, my reason for wanting at least two USB's (especially in the absence of a HD or Micro SD) is for backup purposes (and also easier file transferring), for example if after constant usage of USB1 it's bound to start wearing down and could cause connection defects, then you're pretty much in a spot of bother, so having a second USB port would go some way to reassure you always have two main methods of access. I know a lot of disk usage isn't really required for Midi or Styles (I don't tend to use MP3's a lot), but for each time I need to add new styles or port them over to or from another keyboard (eg, my T4) its wear and tear. Also I use those tiny mini pen drives (16gb max I think) as I don't want anything sticking too far out risking getting accidentally knocked.

I know there's also the USB to Host port, but I presume that's just so you can use your laptop (or PC) to do the file transferring for you, which can be a hassle.