Din Tai Fung
Din Tai Fung is a classic that never disappoints. Although the Taipei shops are still a bit better (and cheaper!), the Causeway Bay location is excellent. Even with a huge area, the restaurant is generally packed from morning until night closing, and for good reason.
The xiao long bao are the best anywhere (sweetie says Kao Chi in Taipei is slightly better, but I disagree), with thin skins and flavorful soup inside. The fried buns are also good, but not as superlative.
Also winning plaudits are the various types of Shanghainese noodles, and the green vegetables, especially pea shoots.
Address: 3/F, Silvercord, 20 Canton Rd
Area: Tsim Sha Tsui
Telephone: 3160 8998
Address: G/F, 68 Yee Woo Street, Causeway Bay
Area: Causeway Bay
Telephone: 2730 6928