Should I buy a washer-dryer or stick with washing machine?

Our current machine (Hotpoint Aquarius) is still going, but I don't think it's got too much life left (we bought it in 2001) and I wanted to do a bit of research before leaping in and buying something in a panic if it does breakdown. I was always against using tumble dryers (environment/cost) in the past, but since our last washing machine purchase, I have had two children and my needs have changed somewhat (particularly with this rubbish weather). We don't have space for a separate dryer, so am considering buying a combined washer/dryer. I'm not convinced though as I've heard they can be temperamental. Does anybody have any thoughts on that and/or recommendations on brands/models. Thanks