It is completely up to you which style of UPVC windows you want in your home; you are also able to have a mixture of styles in your house to fit the needs of different rooms.
Your installer will be able to talk through the different options that suit your home. For example, you might want to have dark colours on window frames at the front of your home and lighter colours at the rear or sliding sash style windows for downstairs rooms and gate style windows upstairs.
You can even choose different glass types in different rooms - an example of this might be to have a reflective finish applied to the glass on the south facing side of your home to control temperatures better while allowing more sunlight to get through on the north facing side.
Talk to your installer about the different needs you have across your home, and they will be delighted to help you to get the perfect finish and to improve your home to suit your needs.