The best product is the one that you can export to make money for yourself.
For instance, India's largest merchandise exports in 2005-06 were gems and jewelry, petroleum products, apparels and so on, as per http://www.infodriveindia.com/Export-Import/Trade-Statistics/Top-Products.aspx#Export_Trade_Statistics_Report_. Obviously, these products are 'best' for a lot of exporters. However, how is this info going to help you if you cannot make money from it? In other words, as far as you are concerned, if you cannot find a buyer and/or source these goods this info is useless!
Therefore, it is best to find out what your contacts abroad need and whether you can supply that. It's as simple as that!