Tumble dryers can use lots of energy but if you have to use one then go for one with a B energy label rating if possible to help keep your energy bills down.
Using the stand-by facility on Televisions, set-top boxes and DVD recorders also adds to your energy bills through continuous, low level energy use. If this is important to you then reduce energy usage by choosing a more efficient model and even better, switch them off when not in use!