From the suggestions that you made, my comments would be as follows:
Albania - too early at the moment - I think that it will be a couple of years before prices really start to take off as the infrastructure is just not there yet.
Calabria - no advice to give you as this is not a market we cover.
Prague - It would be a very safe investment, but not one that is going to increase your capital so much as prices are already high.
My personal tip would be Bratislava as I believe that it still has an enormous amount of growth and is also a very safe investment.
You can read my reasons for tipping it at:
Propertastic! International Property & Real Estate: Property and the Schengen Effect
Slovakia Property Investment: Buy Slovakia Real Estate Resources