After reading this thread, I feel I must point out that Psychology is definitely not a waste of time as everyone is saying here. It can be very useful. While some universities do not give it much rigour on its own, it can complement a set well, and will develop a nice skill-set such as evaluative abilities, essay-writing, memory techniques, which is useful for both uni and the workplace.
Whether or not each subject benefits you is down to a number of factors- your memory ability, your enjoyment levels of the subject at hand, your aspirations for universities, and your chosen subject(s). If you've got some unis in mind, take a look at their advice for A-level combinations.
Basically, don't just take the word of ignorant elitists here on TSR who like to think themselves above everyone else with their A level choices and that they are the authority on what to pick.
You're in Further Education now and it's time to think for yourself and make decisions, not just follow the crowd.