Hiya! I'm exactly the same as you - I've got Maths, Chem and Bio 'for sure' (meaning I'll probably change my mind but for now I'm aiming towards doing them, lol). I hate English and didn't take any Arts at GCSE. I'm still choosing that fourth option.
Have you thought about Geography? I'm definately considering it. It ties with the other three, and also looking at past papers there doesn't seem to be too many huge essays involved.
Or, like the others suggested, Further Maths. (But then you'd think that any one taking Further Maths would like extra Applied Maths too eg. Physics)