All my camera (and voice-recorder) files get renamed to include date/time. The format I currently use is:
YYYYMMDDhhmm_uniqueID.ext
This happens as they're copied from CF card (or
PSD). The ID is a prefix + counter which thus guarantees each filename will be unique even if generated on different machines. The ID is propagated to the final files (and prints, invoices, etc) so customers always have an identifier to use rather than "that nice image of the owl I bought 3 years ago".
Having the date/time in there just makes it easy to sort the files in a directory. Once the files get imported into iView they can be sorted by capture time anyway, but having it in the filename also is just more flexible.
Hooking all the devices up to the laptop every now and then and synchronising their clocks is important. Synchronising them by hand is tedious and not very accurate.