izlog

1. shop window; display window
   Videla sam divne cipele u izlogu. — I saw lovely shoes in the shop window.
   Subotom volimo da šetamo i gledamo izloge. — On Saturdays we like to walk around and window-shop.
2. (figuratively) showcase
   Knez Mihailova je izlog Beograda. — Knez Mihailova Street is Belgrade's showcase.

Vitrina usually means a glass cabinet or counter inside, while izlog is the street-facing shop window.