I am not keen on the houses they show in Grand Designs. None of them look like homes to me. They look soulless with all the glass and white.
I do like house with large windows and I like a bright interior, but there is a limit. I have often thought how lovely those chocolate box cottages look with their thatched roofs and tiny windows. However, they must be so dark and gloomy inside. Unless, of course, they have knocked the whole back of the cottage down and added a huge glass extension 
I do think that Kirsty Allsop has some good ideas on Love it or List it that are practical and stay within budget. Sarah Beeny has also done some similar sensible conversions
I wonder sometime if architects actually look where their designs are going to be built. Currently, there is a block of very expensive apartments being built near us. The most expensive is £1 million. There are (I think) eight apartments in a double story block. They are opposite the sea. The houses at either side were built in the 193o-ish and are white rendered with red roofs. Very traditional. The new block is an angular building in brown brick with brown fake stone on the front. It has large windows but to me it looks like community centre from the 60's. It is totally not in keeping with the others house around it.