Indonesia is made up of over 1700 islands and at the heart is Java where the Jakarta is be found.
Jakarta isn’t really a destination city (imho), but more of a gateway - it’s a bit of a chaotic capital. The shopping here is great and I found quite cheap. For electronics head to Glodok, although I didn’t really enjoy the experience, but Blok M serves more the middle class and includes huge shopping malls. Plaza Indonesia is a really superb designer shopping experience.
There are a couple of museums that worth checking out firstly Jakarta History Museum and Museum Bahari the maritime museum. It has a photo display that recreates voyages from Europe, Ceylon and Singapore; and also craft from around Indonesia.
Merdeka Square has the national monument – the Monas, and in the same area is Sunda Kelapa - the old port, which has many sailing ships including Makassar schooners.