One thing i'll definitley mention is that the Washer/Dryer combo machines you see pull ALOT of electricity - it's one of those things you don't usually hear about as many people prefer the convenience and worry about the running costs later.
The dryer element is typically 3kW, and energized just about the whole time the dryer is running. If we assume a 2-hour drying cycle (which is by no means a liberal estimate for the less efficient machines) and take electricity at a round figure of 10 pence per unit, that works out to 60 pence per load. (Based on guestimates, your mileage may vary, offer void in Podunk, Ariz., etc.)
If you have Economy 7 installed which provides cheaper power at night, it's worth settting the dryer to run on the cheap rate, which is generally less than half the standard rate. It might not save that much on a single load, but over the course of a year it can soon add up, especially if you're a family using the dryer very frequently.