I think you should only take subjects that you're actually going to enjoy.
But it is worth saying that taking further maths will be of great benefit to you if you study economics/physics/comp sci at university - so give that some thought.....
i took maths,bio,econ,chem
had i gone back in time, i'd have taken further maths,chem,physics,econ
... such is life
I think that's a good selection for the courses you want to take at university, but like it's already been said, make sure you enjoy them. No point doing something you hate, it makes it a lot harder
They are fine if you want to keep your options open. However, I'd suggest you make up your mind about what you want to do at uni at the end of year 12, because if you want to do economics, then further maths would benefit you significantly.
Most unis require Biology at an AS Level if not given at A2!
I feel you really need to make a choice about what career path you would really enjoy in the future and go for it. At the moment you have an array of careers which all require different a-levels other than the obvious maths, unless you would like to do 5 a-levels, i could tell you what a'levels i think those courses would be suited for:
Economics: Further Maths, Maths, Economics (Physics or something like History/English)
Medicine: From what I know...Maths, Physics, Chemistry (something else maybe FM or some people have said Biology at AS may be required)
Physics: Physics, Maths, Further Maths (another relevant a'level)
Computer Science: Maths, Further Maths, Physics (another relevant a'level)
You can notice that in almost all of those courses, I feel Further Maths is suited better to prepare for the courses in university but if you don't like maths that much it would be harder to choose FM and succeed at it! However you still make a definite choice or narrow down your choices to help in deciding better suited a'levels for your course
Thanks for the advice people, I feel I cannot simply do further maths, it is only offered to those who are extremely clever at maths, and I would have to study it in my spare time!