What a bizarre post. Honestly. As if many people have to face the choice of choosing a country in the region. Anyways, I disagree.
First, Afghanistan's government is one of the most corrupt in the world. It would suffice to investigate what happens to the aid money they get from the west to rebuild the country. As I query google for "Karzai", Google kindly suggests a bunch of auto-completions. The first one is "Karzai corruption". Enough said. Karzai is hardly a democrat. Just look at the recent elections. He will make sure his clan will remain in power in future. Second, the prospect of political instability is real. No one knows what will happen once Americans fully pull out of the country. The economic prospects are bleak. This is a land-locked, agricultural country surrounded by, as you imply, "not so bright" neighbors.
I would certainly rank Iran higher than Afghanistan. At least the people living in Iran can enjoy a real rule of law without having to sleep with an AK rifle underneath the bed. Iran is much more technologically advanced society, blending old and new, with a significant Christian minority that lives and practices its religion without fear. They have oil. Yes, Iran's rulers are a bunch of crazy theocrats, but what's new?
And then China.. it sort of does not belong in comparison with the rest of Afghan neighbors. For one, it's not muslim. I am certain though that China's economic success will continue. It's a huge market and an emerging economy, ripe with business opportunities. The western businesses are willing to invest tons of money there and even do business on the terms of Chinese government, which are not always nice. Certainly, the Chinese government will have at some point to revise its "social contract" as well as the policies pertaining its economic growth (including environmental policy).