I remember seeing on the "Sequels people would like to see" (or something similar to that) thread that some said they would like to see Mafia 2.
According to 2k Games, it's in development now...
http://www.gamespot.com/news/6177029.html?action=convert&om_clk=latestnews&tag=latestnews;title;2
According to 2k Games, it's in development now...
http://www.gamespot.com/news/6177029.html?action=convert&om_clk=latestnews&tag=latestnews;title;2