Would agree about high beam assist, definitely worth it for the money.
I added park assist as it not only uses the extra sensors for parking itself, but it adds 360 degree coverage for the parking sensors. Also, it was only £150ish
10-12% is pretty much all you'll get as far as discounts go.
Mine's Pure white , but I added leather (not keen on the checquered cloth), dynaudio (I spent £1200 on ICE in my Astra - never again), park assist (cheap option), high beam assist (cheap option), keyless (liked the idea of it and a cheap(ish) option) and rear view camera (cheap option). I also added PP as the diff (on the rare occasions I have a spirited drive) is worth it on it's own and the brakes are superb and look loads better than the non PP brakes. Never driven a non PP car so can't comment on if it's better than a non PP.
Happy with (and would recommend) all my choices of options (although I realise not everyone shares my views on the cloth, dynaudio and PP) as for the money, they all add great functionality to the car