I do not have one yet as I didn't get to attend I/O... I had to pre-order like everyone else

. However, they did go over this a little in the Android wear session (not the main keynote with Sundar). It was mentioned that Android Wear watches would still work as a timepiece and run any .apk that was installed on the watch itself in standalone mode (without a connected smartphone near-by) with a few caveats. If there is no connected smartphone, any task that required Voice, Data, SMS, GPS, etc would not work until the watch was in range of the connected smartphone again.
So, you would definitely be able to tell the time and date, perhaps a pedometer function as well as long as GPS or location data is NOT required. This may be the reason for the 4GB of onboard storage... I can't say that the reason for the storage was made very clear to me at least. You will, obviously, NOT be able to send text messages, use Google Now, or any other service reliant on the phone / data.
It was specifically mentioned that Android Wear uses the phone for the "heavy lifting", so without a connected smartphone I doubt voice control or dictation will work (I.e. no voice memo's) .
Sorry for the long answer, currently Google shows my LG G Watch as leaving the warehouse on July 3rd... As soon as I receive it, I'll post up more

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