I recently bought, played, and beat Lock's Quest. It's a tower-defense game with vague rpg elements. I not only loved playing it, but I also loved watching the story unfold. Well worth the absolutely cheap price at stores.
I chose between that and NinjaTown, which is another t-defense type game apparently. Both are the same price, and I have no idea what NinjaTown is about, but it's next on my list.
If you haven't yet, get a Phoenix Wright: Ace Attorney game. .......... OBJECTION!