Where is the best place to live in West London?

I am moving down towards London and looking for some advise on areas. For my commute the location could be across a relatively large area (I'll describe a sort of square) North East corner: Brent: South East corner: Kingston upon Thames; South West corner: M25/M3; North East corner: M25/M40. Any tips on nice areas would be appreciated, but I know this quite vague so to be a little more specific... I am looking for a house anywhere between 2-4 bed in the region of �500K, some green space for my dog, the ability to park my car. Transport links/ trains are not a priority. I don't expect expert advise on house prices, just any suggestions on nice areas or areas to avoid from locals would be great!