With a single exception, the Panasonic Lumix DMC-GF2 has a great design and touch-screen user interface.
Though not as small as Sony's NEX-5, the GF2 is a comfortable "compact" size for those of us who like a little more heft to our cameras. It also feels a little more balanced when equipped with a longer lens.
Among the sparse features atop the camera are a a decent stereo microphone, albeit one that lacks separation, a dedicated video record button, and a quick-access button for intelligent auto mode. While I'm a big fan of the dedicated video-record buttons, I don't like the feel of this one; it's flush with the top surface and a bit hard to find just by touch.
As with the GH2, I really like the way Panasonic has integrated a set of direct-access controls with the touch screen. Most of the important settings can be accessed directly via buttons--ISO sensitivity, focus area mode, white balance, and drive mode. Panasonic doesn't make you scroll through the menus via the touch screen--a smart move, since that usually requires a level of precision for which these small displays are unsuited.
The combination of direct-access buttons and big virtual buttons, so that you can use each when appropriate, makes Panasonic's touch-screen interface one of my favorites. It works most seamlessly if you use two hands, though (operating the buttons with your right thumb and navigating the screens with your left thumb, almost as if you're texting). You can also program the Q.Menu/Fn button to go directly to any other specific setting that's in the Q.Menu (top).
That said, my main frustration with the interface remains that you can't lock the AF area to prevent it from moving when you accidentally touch the center of the screen. I had to readjust it back to center between almost every shot because of this--an immensely frustrating exercise. (The second screen from the top shows the dynamic-tracking autofocus area, which doesn't have this problem.)