In addition to the traditional PASM exposure modes, Pentax offers a Sensitivity-Priority option (Sv), which automatically adjusts shutter speed and aperture as you scroll through a user-determined range of ISO sensitivity values. It's a nice alternative to the trial-and-error approach to finding the lowest ISO sensitivity that will deliver a desired exposure.
You can program the green button to reset the camera, choose the image settings, show a depth-of-field preview in the viewfinder, apply an effects filter, and reset the autofocus point to center or override the file format settings. I really like Pentax's file override capabilities: you can define a behavior for any given scenario.
Though it doesn't have a lot of the explanations and handholding features that some other entry-level models provide, the K-x's operation is relatively straightfoward, incorporating many familiar conventions that point-and-shoot users are familiar with.
The Info button pulls up an interactive control panel that provides access to almost all the settings: Image controls (saturation, hue, high/low key, contrast and sharpness), cross processing, special effects, automatic HDR, shake reduction, metering, autofocus mode, metering, highlight correction, shadow correction, file format, resolution, compression, distortion correction, and lateral chromatic aberration adjustment.
Though it's a pretty packed display, it's easy to navigate and nothing's hidden in a place that you'll have trouble remembering.