Coolest Former Communist Capital??
I'd vote for Ljubljana, Slovenia!
The outdoor markets have a ton of unique things to offer… plus hanging out at the cafes along Ljubljanica River with all the Slovenian students makes you feel like you're the coolest person on Earth. Everything is so centralized, you can walk (or ride your bike) to all the major attractions. And I DARE you to find a more scenic hang-out than on the town's Triple Bridge on a warm summer night…
Coming in a close second: Budapest, Hungary