If you're intent on Econ & Pol then them with Hist and Maths (unless, seen as you didn't mention it you have a strong aversion to Hist, in which case: EngLit, Geog, FM or a science).
As I see it, the best combination would be Maths, FM, History and Economics, but it is also important to do what you enjoy.
My advice, however, would be not Politics - it's comparatively Mickey Mouse compared to the 'traditionals'.