Haarts estate agents have made some crude calculations to give you an idea of what external factors affect the value of your home, and how much value they add or take away. Let's cut to the chase:

The Good

Mainline tube/railway station: 12%
Top state school: 11%
Motorway/dual carriageway links: 9%
Open countryside/park: 9%
Vibrant social scene: restaurant/pubs: 6%
Quality food store (Waitrose/M&S): 4%
High street facilities (e.g. banks and newsagents): 3%
Sports club/exercise facilities: 2%
Good NHS hospital: 2%
Cinema/entertainment: 1%

The Bad

Run-down/derelict houses: -12%
Late licence music venue/takeaway venues: -11%
Derelict land: -9%
Airport flight path: -9%
Waste/refuse station: -8%
Busy road: -8%

The Ugly

Nightmare neighbours: -7%
Poorly-rated comprehensive school: -6%
Railway line: -5%
Mobile phone/telecom masts: -4%

More here.