I have an e-commerce site and the company is registered in Florida, US. I'm located in Israel, and I have an idea to create a social network site. My main question is which of the following options is the best:
I think you should contact a lawyer and an accountant and get official consultations.
First, I guess I've never heard of Florida being a great place to create a legal structure for a company, Delaware I believe is one of the most common.
In terms of you being a foreign national doing business in another country, in this case the United States, I have no knowledge or experience on the matter; though it would be interesting to know how hard it is to do.
In terms of starting an Israeli based company instead of one in the US, it depends on the market, but I'd say if the network of people you serve in a region, then have the business in that region would increase your odds of success.
UPDATE: Another issue, which might even be the reason you've got a business in Florida - shipping across international lines can not online be a huge pain in some cases, but also add to the cost of doing business in a remote region.
Based on your question, there are two parts: