Most travellers don't spend much time in Jakarta. They either skip it all together or use it as a travel hub – and for good reason. It's not because Jakarta is horrible, just congested and very low on sights. But that said, you can with some effort spend a day or two of sightseeing and eating some nice food. The usual city tour goes around the National Monument, where you also find the cathedral, grand mosque and some, by Indonesian standards, fine government buildings. For the second day of sights, head to old town Kota (also called Batavia), which once was "the Jewel of Asia" during the Dutch ruling in the 16th-19th century. Of course, not much is left from that time.
On a positive note, it should be mentioned that you don't see much poverty in the central Jakarta and the pace is very slow considering it's Asian metropolis.