I used to have the most badass case for my DSi. It was a plastic shell that snapped on, and you could put various Mega Man-themed slips in it to change the design. (I think there was a red, blue, and green one.) The best part about it was that on the rear of the system, it had 3 slots to put games in. This way, I could still slip it in my pocket, and I had 4 games with me at any time.
I now have a 3DS and a 3DS XL and I must've gone through like, 3-4 cases until I got fed up with them and threw them out the window.
What cases do you all use? I'd KILL for one that allowed me to store the games behind the system. I do not want a pouch or a portfolio. Just an attached shell. Does such a thing exist?