Very topical. We've just bought a dehumidifier as we have a bit of trouble to condensation and damp on the ceilings.

Our windows are double-glazed, with trickle vents (most are closed this time of year, but not all as I don't like to wave goodbye to our heat as the place is difficult enough to keep warm as it is) and we have cavity wall insulation, but we still get more damp than I would like. We have an 'Owl' energy monitor and it measures temperature/humidity too. Our bungalow sits at around 60-65%, creeping to 70% when there is washing hanging around the place being dried. Apparently 40% is a more acceptable level. They do wonders for drying washing too, so they say.

We bought an Ebac 2650e, it's in the price ball-park of that one you posted Dave, £175 from Argos. OK, so its not quite so nice looking, but it really does look OK. It gets VERY good reviews, which was mainly what we went for. We only got it last night and still need to have a play around with it, but I will let you know how we get on.