Some ideas for a modularised set of gadgets that work together in a personal network [e.g., "on the body"]:

• PDA [provides touch sensitive screen, other input possibilities, wifi, some storage]
• Music player [provides hdd storage, has small screen and controls for standalone functioning]
• Cellphone [provides gsm/3G uplink, possibly snapshot camera/video chat possibilities]
• Wireless foldable keyboard
• GPS/Galileo mouse
• Digital camera [can use GPS for recording coordinates in EXIF, bluetooth to store to hdd alongside its own card storage, pda can show pictures from hdd on its biggish screen]
• Wristwatch with stats/phone & music controls etc
• [Bluetooth?] stereo headset with microphone

Bluetooth 2 or low-power, quite highspeed equivalent connects it all. The PDA can control the music player and the cellphone [answer/make calls, send text messages etc].