If you bought a DS for Diamond/Pearl/HG/SS/BW, then it only makes sense you should get a 3DS for XY, and all future 3ds pokemon games. Though its up to you and your econimic situation, and the investment you feel would be worth. Pokemon is awesome, ovbiously, and you'll hear plenty of praise here, and millions have bought a 3ds just for x/y. I would recommend it, plus there's lot of awesome games for 3ds, (luigi's mansion, mario kart, monster hunter to name a few)