I bought a Etrex with a serial cable for 100 UKP and today it arrived.
I have not been so enthralled by a gadget for years.
It tells the time. It can figure out north if you are moving. It tells you exactly where you are within say 10m. You can put down way points. It draws a map of your movements. It can estimate when you will reach a destination by calculating the average speed. It is completely cool!
The two downsides I have seen so far as the batteries will not last more than a day. Also it needs to have a clear view of the sky for it to work. I wish it was smaller too. I have also found it a problem to read co-ordinates off a ordnance map accurately. Perhaps I will get better at this. I should find out how to download maps onto my computer.
Another aspect to running around with this device is Geocaching.
People hide a log book somewhere for you to find at particular co-ordinates. I’ll try find one tomorrow near where I live in Cornwall.