The most upscale part of the larger Bukit Bintang district (Golden Triangle area), Changkat Bukit Bintang is a few blocks of renovated colonial buildings that house an international array of nightlife and cuisine. The concentration of establishments between Jalan Sahabat and Tenkat Tongshin is remarkable, although there won't be all that many opportunities to enjoy authentic Malaysia.
There is hardly a more popular avenue come the weekend; pub-style establishments like Werner's and Healy Mac's overflow with good vibes and brews, while exclusive clubs like Movida and Elixir have the music and lights to make you dizzy for a cocktail. Most places are restaurants during the day, when travelers may be fooled into thinking they've walked into a more mundane part of the city; don't be fooled, for many of the hottest places to hang out late-night are crammed onto this small street. Grab tapas, Italian, Vietnamese, Western standards, and much more during the evening and, if it's your style, pub crawl your way up and down the street.
Note:Also of interest is the constantly buzzing Jalan Alor, a hawker street that runs perpendicularly at the western end of Changkat Bukit Bintang. This is the REAL Kuala Lumpur; you won't see a ton of aimless tourists here, but you will find a great selection of local cuisines.