The two most loved dolls my girls have ever owned were both just dolls, they didn't do anything. Well, with a bit of imagination they did everything!!
Baby suzy cost about a fiver and was an instant hit because, being all plastic (which is rare in a doll these days) she could swim in the bath. She still gets dunked now and again and we've had her for about 4 years.
Baby Lucy, £10 from ELC one xmas, became a part of the family, she had her own chair at the table and even got xmas presents one year! She was very good company when they all went off to school too.
I did give in to pester power a couple of times and buy dolls that required batteries, the batteries ran out and nobody ever asked for them to be replaced and they were re-homed within a year.