nature and wildlife, architecture and indoor architecture (cathedrals), portrets

These are very similar cameras. But the stats show that the K-5 is slightly better than the D7000 including an extra stop of ISO sensitivity -- and it's less expensive.  Image stabilization (sensor shift) is built in to the camera, which might save you from having to buy expensive Nikon VR lenses for wildlife shooting.

Having said that, the button layout on the D7000 is closer to what you're familiar with on the 30D