The important thing to remember about which countries F1 chooses to go to is the business opportunities in those countries. For this very reason the most important countries for F1 right now are China, India and the US. To a lesser extent you could argue Brazil, the UK, Japan and Germany also fit into this category, and if we had a race in Mexico that probably would too. In future it is highly likely with continuing trends that we should expect an African country to be placed in this category. From my knowledge a shortlist of South Africa (obvious), Nigeria, Kenya or Ghana may be possible in future years.
Away from this, you have tracks which fit into the historical/traditional category and along with Britain, Japan and Germany from the above category, here you would place countries such as Monaco, Italy, Australia, France, Belgium, and Canada. It is of no surprise that these locations are amongst the favourites of F1 fans.
From there you have countries which are willing to foot the bill to be a part of it all, and of the current fixtures on the calender you have Malaysia, Bahrain, Abu Dhabi, Singapore and South Korea. These are all essentially replaceable, and when Russia joins in 2014, it will be in this category.
That leaves the two current races in Spain and Hungary. The former is simply exploiting the explosion in interest in Spain following Alonso's success, and is similar to the two races in Germany we had during the Schumi years. Some may argue the Spanish race deserves to be considered a historical/traditional race, but I remain to be convinced, especially when their current unemployment rate stands at 25% and the country has few interests in four wheeled motorsport aside from Alonso, and to a far lesser extent, HRT. Portugal lost their race very easily and I can see Spain going the same way.
Hungary currently caters for what is a fairly large market in Eastern Europe, but the likelihood of this diminishing once Russia is on the calender in 2014 is likely, and with the track never that favourable in the eyes of casual fans, I question the likelihood of it being a fixture for the long term.
Ultimately though, money will talk, and aside from the key markets mentioned at the start of this post, F1 will go pretty much anywhere if the money is handed over. All things go in cycles though and eventually when markets become more and more saturated, we will see a return to old tracks once more.
That's right Eddie, that was me with the banner, Spanish GP, 2002. This pile of legal forms won't fill itself in you know...