One of the best street food markets in central Bangkok is Sukumvit Soi 38 - right by Thong Lo station on the BTS. Some of the stalls are open during the day, but it doesn't really kick off until about 5pm.

The fruit shakes are addictive, especially the passion fruit one or just go for the old and trusted banana! Other recommendations are the fried tofu (trust me, amazing!), the som tum (papaya salad), the dessert - mango and sticky rice...to be honest, almost anything on this street is delicious! Just watch your backs, as there is always quite a lot of traffic!