Well, for me I would take Business or Accounting instead if economics but that is because I find them more interesting. It differs to different people though.
Other subjects are alright, I took French, English, Math, Business, Physics, Chemistry, ICT and Accounting.
Why didn't you consider taking ICT ?
No need to be scared. IGCSE is not tough at all, it just needs hard work and I know many people who studied o-levels alone at home yet they got all A's and A*'s.
Plus, studentforums.biz will always be there for you if you have any doubts. Plenty of helpful people are always there for help and if you need ANY resources for any subject you can always ask me.
Good Luck. =]