Out of those, i've played Broken Sword games, Jack Keane and Tunguska. Broken Sword 1 and 2 are classics, great games, third is not bad too. Jack Keane is similar to Ankh series, and is one of the better comic adventures in past couple of years (look for Ceville too). Tunguska is a classic mystery adventure with decent story. The company behind it is responsible for Lost Horizon too, as well as Secret Files 2, but i think the original Tunguska is still somewhat more challenging in terms of the puzzles.
By the way, you've got me there for a moment - there was a countryman of yours with the same name - Dimitris Manos, who ran adventure online magazine, so i thought you're him for a second
