Standard Vx pads have always been good. It really does depend on what you want and are they going to serve a purpose? If you've been happy with your brakes until now then there's little pint in changing the set up. If you want to start going down the fast road use then upgrading the discs to 308mmis the route to go but this can be expensive when you add on the price of the caliper brackets.
I have 308mm 16 groove Courtenay discs and EBC Redstuff Ceramic pads on the front. They are outstanding on my car! On my wifes Zafira i'm using the OE set up and that does the job perfectly.