The situation in Nepal is a very tenuous one that I don't think any of us "experts" can truly evaluate. Even the Nepalese people are very in the dark or are being mis-lead about what is actually happening in their own country. I have lived in Nepal on and off since 1996 and things after 1996 were always dangerous, but only in very remote regions, far from us tourists. I had a couple of close calls but nothing to write home about. There are many theories on the 'maoists' and who supports them and their idealogy. One thing to remember is that the 'maoists' only make up a small portion of a dual sided party. The CPN-UML (communist party nepal-unified marxist leninist) is a legitimate party in Nepal with some serious grievences with the ruling aristocracy. The Nepalese government and royal family are some of the most corrupt in the world and continue to keep one of the poorest nations in the world poor, while the aristocary keep moving up the list. Rumor has it that the previous king of Nepal, in the early 90's was possibly the 5th richest man in the world!
As for us climbers- many regions are unsafe, but climbing is still very viable. Pay attention to hot zones and pick accordingly. Half-assed updates can be found at www.nepalnews.com