The screen you use is completely your own choice. It all depends on the brightness, output type you want to use, how many A/V modes you need the monitor to have, and the bottom line. How much money are you willing to spend?
So to just ask which screen you should use would be too broad of a question. Everyone will have their own inputs.
Here are some decent screens that should fit double din. Again, the best thing you can do is do your own research and pick out what's important to you.