Well I was going to suggest one like mine, because it has been a right faithful old dog
An Etrex Vista Hcx - They were going for £50 or £60 a couple of years ago, but I see from a brief google, that they are going for more like £170 - £180 these days
I think the new Garmin equivalent is the etrex 20, but my mate got one, and found that the battery life is about 20 hours as opposed to 36, so maybe thats why there are so many folk trying to get their hands on the old models? Seems bizarre that the older ones are going for so much
Makes me think the newer models arent all Garmin say they are..