If you don’t have time to roam around in city and still want to see it. The best way is to get on to the tallest possible building for the entire view of the city.
We did exactly same while in Kuala Lumpur. Early morning from Sky bridge of Twin towers we got great view of KL. To be on Sky bridge is great experience but view was very limited. Sky Bridge is only 170 meters high. :)
For more spectacular view we went to KL Menara Tower also referred as KL Tower. Tower’s height up to roof is 335 Meters and up to antenna 421 meters. 360° viewing observatory is located at 250 Meters. High speed elevators take you at that height within a minute.
Many huge binoculars are kept in the observatory. View of KL city was really spectacular. (See some of the photos). Twin towers also could be seen.