I have read few other threads about coming back to Nepal and wanted to write something here.
My situation may be different from others but it may just provide a different perspective.
I am a Nepali by birth and Nepali at heart :) and lived in the US for 15 years in which time I had accumulated a good savings, a house as well as a US Citizenship. After being a cog of the wheel called the American economy for 15 years I decided it was time to come back to my roots. Obviously it was a very tough decision but as few others mentioned, it seemed to be the right time since I too wanted to spend time with family. My wife and I agreed that we needed to give our 4 yr old son a chance to grow up and experience Nepal as well.
Inspite of major difficulties in living here, one of the most important one is finances without a doubt. We felt that we were covered because we owned property in the US which we had rented out plus some investment and it provided approximately $3000 to $4000 a month income. With this income we were not much affected by a lot of points that poster saami pointed out such as politics, luxury and money. The part about security is always a concern no matter where you are. Even in the US there are always cases of crazy crimes which you never know you can become a victim of.
For electricity and water you can always find an alternate source if you can dish out some money. Transportation can be a major hassle but personally I don't have to go to work on a daily basis so it's not much of a problem. Pollution is a major problem but if you have AC in your car then it's not a big deal.
I think it is the best decision I made because I had begun to feel soffocated in the day to day life of commuting back and forth from work. Life had begun to feel very monotonous day in day out. We come to the US for the American dream, go to college, get a good job, get married, get a kid, get a nice house, nice car. The question after that became - what now? Maybe get a bigger house, bigger car. It ends up there is not much to look forward to.
In Nepal, although it takes a little bit of time to get used to the pollution and sickness, over time you build up a good immune system and you can survive relatively well. The day to day life is so much relaxed because you don't have to be on the run constantly. Even schools for kids are so much better than in the US. It might depend on the school but there is more all round growth than in a public school in US. My kid being able to play with his cousins and have a more social life than being cooped up in the house for half the year because it's too cold to go out or because of lack of social opportunities.
We've been here in nepal for three years now and we've gone back to the US twice to check on things and my son can't wait to come back to Nepal each time because he's so much happier here. There are always challanges here too but nothing too big like feeling like a zombie working day in day out without too much to look forward to. Even here, well there is not much to look forward to but the quality of living interaction is so much better you look forward to buying some tarkari or go to the departmental store, or go to eat at Bakery with friends at moments notice, riding your motorbike, lazying out on the sun, to name a few.
It might be difficult to come back Nepal for good but if you are financially secure then I don't see why not.
