I think we'd like proper usb host for a number of reasons:
1/ external mass storage - hard drive, flash drive, digital camera etc
2/ non-mass-storage digital camera (can't remember the protocol, but gphoto can do it)
3/ communications devices such as the HSDPA/3G modems
4/ comms w non-bluetooth mobile phone for synchronisation, sms etc
5/ serial, usb to parallel, and other I/O expanders
6/ scanner
7/ keyboard, mouse, trackball etc

not in any particular order of priority, just a list as I thought of them.