There is also another debate that could be taken here, with the rising fees and endless job-search for that high paid job. Is it better to do a science-based degree or an arty degree? Which one has the best option for a golden job to pay for your training?
It all depends on your motivation for going to uni. If you genuinely have an interest in a particular area of academia you should probably study that. It's a shame that academic study is increasingly just seen as a means to an end, rather than an end in its own right.
That said, if you are going to uni mostly to get a good job, I would say do a rigorous academic subject e.g. history, law, sciences, maths, economics. Beyond that I think degree classification is more important than subject. I know people from all these backgrounds in law firms, professional services firms and investment banks. There are many bankers and accountants with history degrees and lawyers with maths degrees.
Some more specific jobs obviously require quantitative or specialist degrees/further study e.g. IT roles, quant roles in banks, actuarial positions.
Most of these employers will look at A level results as much as degree results, in my experience.
If you just want to earn as much as possible then go for investment banking where graduates start on circa £45k and front office staff (i.e. equity sales/traders/M&A) can be earning six figures by their mid twenties if they do well. Not easy to get into though, high attrition rate and an absolutely brutal environment to work in.