Qt is an excellent application toolkit and overall the best for C++. While some large projects use Qt (KDE for example), I haven't seen many games using it. So I decided to make my own. But what does Qt provide that may be useful when writing a game (in my case a 2D game)?
You should definitely take a look at the Qt Graphics View Framework, it does provide a nice hardware accelerated 2D scene graph (QtGraphicsScene).
There are games made with Qt, KDE has a lot of them, see http://games.kde.org/
Most of them are made using the graphics view framework, and the svg renderer.