Best screen size

I am making a game for mobile devices and was wondering what the community thinks is the best screen size to produce in order to work over different devices?I know that in the game properties i can set the app to scale itself to the size of the screen.

whatever size you want really. With fullscreen mode and especially fullscreen letterbox mode its not really an issue

Take a look here scirra.com/forum/topic52806.html

I's kind of the same ; )

It is not possible to make a single window size that works on all devices. You must support multiple screen sizes. See supporting multiple screen sizes.