If you both work, a short and easy commute is essential, IME.
Herne Hill would be excellent as the number 3 bus goes directly to Millbank, while the Thameslink Overground goes quickly to the City. Also the fabulous Brockwell Park and Lido would be on your doorstep. Good independent schools v close by, less choice for state, though Rosendale is very good.
Brixton is great, you need to be on the doorstep of Sudbourne School for Brixton state schools - but it has the Ritzy Cinema, Brockwell Park, good shopping and the TUBE!
Clapham is great, on the tube, good shopping and cinema, the common - buy v close to Clapham Manor for good state primary.
You might like East Dulwich / Lordship lane area - good shopping and cafes, I think the tube is rumoured to be on it's way there, but otherwise the travel is a bit tortuous.
Balham v close to Telferscot School is very nice, close to tube and good facilities
Excellent value but not as glam is Streatham Hill, especially the so-called 'ABCD' roads, of which Downton, Wavertree, Nuthurst and Normanhurst should get you into sought after Streatham Wells state primary and then Dunraven secondary, with the lovely Independent Streatham and Clapham Girls at the end of the road. Choice of 2 good overground stations 10ins walk, or 10 min bus ride to Brixton.