If you are thinking physics related degrees, drop biology. Even if you wanted to go into medicine, you wouldn't necessarily need biology - I know UCL for example only require Biology to AS level, so you could always do one, then drop it at the end of the year and do another AS alongside your three A Levels.
A subject like English is perfect to take alongside science subjects, it shows you are an 'all rounder' and not just somebody who can reel of sums, facts and figures. Universities are becoming so much more competitive, it will do you no harm at all to have some variation in your qualification and if you change your mind about doing a science degree, you've got some room to move by having an arts subject.