...a bicycle shop. Somewhere which sells bikes, parts, accessories and does repairs and servicing. Herne Hill Bicycles is great, as is Brixton Cycles but both are always booked weeks in advance. Plus there's the hassle of travelling back and forth on the bus after dropping my bike off. Judging by the number of cycists in the area, I'm sure that a good bike shop would do a brisk trade and there's lots of empty shops on side streets just waiting to be recuscitated.