Could anyone recommend a reliable wrist-attached GPS ?

Garmin Foretex. Got mine off of Amazon a few years back and it's fantastic.

Just like the other responses I would say garmin foretrex 401. I bought mine 5 years ago and it's still going strong. Although it's used more for geocaching rather than in the field since during the field I'd rather use a map, protractor, and maybe a compass.

Garemin Foretrex 401. You would hardly find anything better without getting broke.