All around Vladikavkaz, you'll find these mobile coffee kiosks. They seem to be open 24/7 (or at least stay open very late). The coffee is really good. Prices are reasonable.

Overall, the city is very pleasant. Lots of old buildings, plenty of lush greenery. In the evening, the center feels very cozy, with crowds of people strolling around. Tons of cafes and eateries with delicious food. But I'll tell you more about the food separately.