Ace Attorney 3 on the DS's story is great. If you've played Ace Attorney 1 & 2. It takes a lot of the backstory of the previous two games and brings them into the present, so while it's great on its own you have to be familiar with the history for maximum fanservice.

Indigo Prophecy/Fahrenheit had some really great moments as well, and that's on the PC. When it came out in the 'States it was rated M, but they rereleased it online as a 'Director's cut' with an AO rating. I haven't played that one, but apparently the things they cut out of the M game weren't very important to the plot.