We recently discovered chocolate-covered grapes at Karamel-Kuche in Germany, and they have become a must-stop now. Not a combination you'd necessary think of, but it works...and works well.
I'm also a fan of the shawarma (platter or wrap) at Tangierine Cafe in Morocco. It's more of a meal than a snack, but great to share if you still want to convince yourself it's just a snack!
On the opposite end of the spectrum, when I snacked around the world recently, I opted for strawberry red bean ice cream from China and was very disappointed when it was handed to me in one of the pull-off top cardboard cups with the wooden spoon. Still got it, with a hope that the unique flavor would overcome the presentation....but I was wrong. It was also frozen solid, which made it that much more difficult to eat as we strolled along. If looking for a snack in China, I'd steer you elsewhere (egg roll from cart?).