It depends on how you are going to earn from your blog and the content on your blog.
If your content is specific to a country, then you can target that country from within International targeting.
If your content is general, and you earn from Advertising only, then i recommend that you keep international targeting as USA / UK so that you get higher CPC.
In case of affiliate marketing also, you need to decide which affiliates you are using. For example - if i am using Amazon India, i will keep international targeting pointed to country INDIA.