They've all got their merits. FFX got an hd-makeover recently, so that's a pretty good choice. I loved 12, but lots of people thought the gambit system was too complex (8 had a similar problem with really-unnecessarily-complicated battle systems). If you can get into it though, they're both great games. 13 made me lose all hope in the series, is how much I hated that, so.... yeah..... but 7-10, 12, and Tactics are great.