The K-7 is a great camera, no doubt about that. I bought mine when it was released (before any reviews were out, and before it dropped in price any......), and had to deal with the initial issues such as the green line in video mode and some annoying settings that were missing from the custom menu functions before the later firmwares. But after those fixes, I have been really happy with the camera.
I especially love the ruggedness of the camera. I have recently been into backpacking, and the several times that I have gone, the K-7 has gone with me. I attach it to my pack shoulder harness using some quick release buckles, and it hangs around my sternum all day long while we walk. The WR (+ a DA*) keeps the dust & rain out, so I don't have much to worry about other than taking some nice pics. I take good care of my equipment, but not having to worry about minor environmental hazards is a huge bonus in my book.
A lot of people complain about the high ISO capabilities of this camera, but that doesn't bother me very much. I shoot at whatever ISO I need to for a given shot, and clean up the noise afterwards if it really matters that much. After having said that, I love to stick to the lower ISOs to get the awesome detail and rendering that the sensor can capture there. Higher ISOs require exposure to be dead on or you will have problems with PP (sometimes I just force myself to make it to a B/W conversion). Either way, the camera is just a tool and every tool has limitations that the user has to deal with. This is one of them.
The one area that I have found lacking for the K-7 is for astrophotography. That is the main reason that I would want to upgrade to a newer model such as the K-5. I don't even attempt shots like that very often, but I don't like fighting with the forced DFS when I am out camping and the sky is crystal clear with thousands of stars.
K-7 loves hiking across the mountains
K-7 loves hiking through the valleys
K-7 loves playing at the beach
K-7 loves produces beautiful colors
K-7 loves kayaking (photos taken by my wife from another kayak with a Canon G7)
What's not to love?