Doctor = medicine you really should do Biology and Chemistry - though there might be a few medicals which will consider you with one, if your serious about this only doing one is a pretty bad idea. (Maths/Physics is essential for some but definitely not all schools)
Sound engineer Electronics IT/Computing would probably be most useful along perhaps with something like Physics - though me brother became a sound engineer without any A levels, so this may be fairly flexible depending on which route you plan to take.
IT Technician - No idea probably IT/Computing (Maths if you can stomach it really helps with the other sciences I wish I took the AS despite hating GCSE) /Physics then something of your choice.
Engineer - Electronics Maths Physics and History would seem like sensible choice but I suspect Maths and Physics would be the most important and everything else would be pretty flexible.
Politician - History, English, then two sciences or maths and a science would make you a well rounded candidate.
I think really you need to decide what you want to do and then rapidly study the requirements of your chosen career/s.