If you have the time check out this article.
Why Startups Paul Graham has the credentials that make his essay worthy (see his bio). I agree with most of his points. Some of them are political in nature but they all have merits.
Tax rates are probably (imo) the biggest factor to start up success. Back in the early 90's I ran my own tech/export company. Part of my plan was to keep margins thin for the first 5 years to build a client base. Our state changed governors and they added a corporate franchise tax. There was very little incentive for me to increase my cost to cover the extra tax so I sold out and moved on.
The top 10
1.) It allows immigration
2.) It is rich
3.) It is not a police state
4.) Its universities are better
5.) It has less restrictive labor laws
6.) Work is not strictly identified with having a job
7.) It has fewer regulations
8.) It has a large domestic market
9.) It has venture capital funding
10.) Americans change careers more often
If you're interested in startups, he has other articles on his site you might like.