It would be very useful to have a setup which allows your profiles to change automatically based on your location. Obviously this isn't practical by using GPS because that'll suck the battery dry, but since most people will have wifi on permanently, it might be possible to use that instead.
Additionally, it would be pretty swish to have the device automatically open and close applications based on these profiles. Other changes could include ringtone/vibrate, power settings, gps on/off, bluetooth on/off, etc.
Simply, the device could be set to activate profile A (vibrate, calendar, calculator, VNC, bluetooth, etc) when connected to, say, work_wifi_network_abc, and then deactivate when it is no longer connected. The device may then activate Profile B (ringtones, bluetooth, music, etc) when connected to home_wifi network.