Go into Terminal 5.
Best place i think for Photos now!
I went there and it's some amazing views. Oh and when i mean T5 not for a flight but there is viewing areas on each end of the terminal for 09R and 09L.
Walk past the 09R/L Threshold and up the Ramp towards the T5 Bus station.
Up the escalator and into the check in area. Either the south or North side there is huge windows and space to view with seats.
Obviously you can get better but this was with a mobile phone!
http://www.flightsimworld.com/forums...owtopic=142448
I never took these but i went the same place as this person did.