Heck I'm still playing Dragon Quest 9 since September.
Tell me about it. I'm still playing it from launch in July. I finished the campaign months ago, but there is still so much to do. The treasure maps alone could last 1000+ hours if you let each boss get to 99. Definitely the "one game you would want on a desert island".
"One of the ways I gauge a DS game is by recharges. "...Tycho (Penny Arcade)