I'm constantly trying to broaden my London horizons and travel to obscure areas to eat and experience the many cultures the city houses. I really enjoy travelling to areas with distinctive ethnic attributes, i.e., the Broadway in Southall, where you feel a bit like you've trekked across the world rather than 20 minutes on a train, and thought a comprehensive thread would be a great addition to the board.
Off the top of my head :
Afro-Caribbean : Brixton, Harlesden, Stonebridge, Tottenham, Dalston, Lewisham, Peckham
Bengali : Whitechapel / Tower Hamlets
Greek - Palmers Green
Japanese: Ealing, Golders Green, East Finchley
Jewish : Golders Green, Stanford Hill
Korean : New Malden
Middle Eastern: Edgware Road
South Asian: Southall
Vietnamese: Deptford, Shoreditch (Kingsland Road), Hackey (Mare Street)
Please feel free to add (and correct me if mine are wrong).