The key to understanding Melbourne is it's all about the laneways (alleyways) and NOT the main roads. It's a city where the best bars and coolest restaurants are found hidden in small laneways and not on strip.
If you're in Melbourne on a week day, then one of the best places for Lunch is anywhere on DeGraves St or Centre Place. You'll experience the real buzz of the city at lunch time and be spoilt for choice with good, quick food.
Degraves St runs between Flinders St and Little Flinders St, halfway between Elizabeth Street and Swanston Streets. It's basically opposite Flinders street station.
Centre Place is the very small laneway that is the continuation of Degraves Street. Don't forget to lookup as well! The Majorca Building on the corner of Centre Place and Little Flinders is stunning.