Definitely Montenegro, since 2006 - 2007 the prices are abnormally big for this small but beautiful country, for example 1 m2 in Montenegro is more then Palma De Majorca, (I know because I work there too).
Why? Because first buyers from Russia and Ireland mostly is the ones who rises the prices (not the local people as you might think), because they knowed that Montenegro will be the most waned real estate market in next few years. You don`t need the better proof from this: if somebody (and this year was lots of them) is willing to pay 5000 euros per 1m2 of the coastal residence in this small country, then definitely something is telling me that this will be the real, real estate BOOM now when the prices are going down because everyone is starting to build and therefore is much more villas, houses and apartments now available to middle class buyers !!!