Bluetooth Wristwatch

Your watch should be part of your personal area network. When your phone rings (which may happen silently on the watch display before the vibrator goes off in the phone itself), the number should be displayed on your watch, and the watch buttons should do what your phone buttons would (send to voicemail, answer on headset, etc.).

When a meeting reminder goes off in yhour PDA or notebook, the reminder text should appear on the watch, and the watch buttons can handle the "OK" or "defer" functions. Even better, the watch should contain a replica of your reminders. When you'rfe carrying both your watch and your PDA, the reminder appears on the watch. When you have only one device with you, that device (watch, PDA, or even phone) displays the reminder. You should never get bugged for the same thing by two devices.

Some other alerts would be interesting to see on your watch as well. For example the popup alerts from nextbus.com (e.g. "the bus is 2 minutes away") would be useful on your watch. This could work if the watch could see some other device with internet (or maybe SMS) connectivity.

Of course a connected watch could always sync itself to a better time source via NTP, and report on the last time it did so when prompted. It could also act as an NTP server to other clocks under your control, to sync thgem when you come near (assuming a bluetooth interface is cheaper or uses less power than a WWV receiver for the satellite clocks).

The Seiko thing (see Google link below) is still (as far as I can tell) a prototype (therefore not necessarily baked). Its exact capabilities are not precisely known (so it may not do these things). The propotype (and the wrist computer from IBM that matches the same search) are enormous things like a Dick Tracy wrist TV. This isn't baked until it looks like a real watch (with hands and an LCD behind or in front of it) and I can buy one for $50.

[2021 update] Obviously this has been baked for a long time now. My Apple Watch is exactly what I had in mind, even though it cost quite a bit more that $50.