This could be an entire discussion on it's own :) , if you are in the U.K. then see what Crossrail is doing to property development and prices. Wherever a building/construction company find's permission to build, they are building blocks of flats. That should have an expected outcome of price dilution due to availability BUT doesn't seem like that's happening. The worse thing I fear that may happen is that areas which have houses at the moment may start converting into areas with flats. There already are more than one examples of that happening in the area I live. Decent areas of London are out anybody's price range. Too many straight out cash buyers wanting to park their monies :-/
Yes, I'm talking about the UK (and Ireland)