Depends what you want to do as a career. Russel group generally want 1 or 2 of what they call "facilitating subjects" these are: English literature, History, Modern languages, Classical languages, Mathematics+further, Physics, Chemistry, Biology and Geography.
So for example if I wanted to get into economics I would take: Maths, Economics and History. If I wanted to get into politics i'd take: History, English lit and politics. If I wanted to get into business id take: maths, a modern language and business. In my opinion If you really don't know what you want to do take 3 facilitating subjects.