I don't think each area should havea theme. It would make the house look tacky and OTT. I'd love to see something along the lines of BB5 and BB6. Contemporary, ultra modern, intersting, designer and lots of abnormal angles with the addition of lots of bright colours mirrors and glass
Housing external areas (Eg BB5 bedroom/bathroom/pamper den and BB6 living room/showers) All following the one same theme as the houses always do:
2 - Cabin fever
4 - Cacoon
5 - Evil
6 - No privacy
7 - Inside out
8 - Impractical/grown up
So as a summary, a house with little privacy, interesting features, bold/bright colours and still nice to look at.