In designing and building a game's interface, I am tending towards using openGL to build the interface and I wanted to get an idea from the folks here as what their preferences are for interface building?
It is depends what type of game you are creating, if you creating a cRPG like a some of hack 'n slash games, you must think about players speeds of reaction, and if you creating a strategy game your interfece will be totally different.
The game that I have in mind will a simple (I hope) 2-D interface composed for five viewing areas.
A central map area
A ticker tape area to display stock prices
A player statistics area to view the players vitals
An actions area to view the actions that the computer players are taking.
There will also be a number of dialogues that would be displayed to user for announcements and the like that would need to displayed as the turn progresses.
Try "IndieDB":http://www.indiedb.com/ here. This is where some game makers hang out, it might give you some good ideas.
Not sure if I fully understand your question, I'm not clear about the definition of interface. If you refer to a game engine, then I think Irrlicht works extremely well for 2D as well a 3D. It has the GUI to do exactly what you want to do. - All am doing right now is a redo of Tetris for my phone. It needs only two paint controls, and three print out sections - Qt gives more than I need. The more I study Qt, the more realize how extensive their classes are.
Also some game engines have worked to integrate Qt as their 2D interfacing option. Check Delta3D. It's open source and free.
It depends upon how you will launch your game. If you want it to only reside on a windows(as DirectX is platform Dependant) based machine, then by all means use DirectX(and yes you can use it with Qt from what i understand, but you must override the Qt paint event to null in order to render properly), DirectX tends to be much easier to use than openGl, and by easier I simply mean you can do more in less lines of code generally. I have used both and it simply boils down to preference. If you use openGl, you do not have to do any workarounds, if you use DirectX to create the UI you do.