Ukraine's strategic importance

For those of us who have been following the unrest in Ukraine, the last couple of days have been quite hectic. Kiev is in turmoil, Lviv has proclaimed its desire for independence, ethnic Russian separatism is rising in Crimea and the Euromaiden demonstrations have so far claimed the lives of more than a hundred people. The country is broken, falling apart and fragmenting into smaller entities, some analysts are calling Ukraine the next Yugoslavia. But what exactly is so special about this country? Why are the Europeans even in Ukraine? And what are Russia's interests in Kiev?