Makati houses most of the big hotels like Makati Shangri-la, The Peninsula, Mandarin Hotel, New World Renaissance Hotel. It is the largest and most central business district where most major companies and banks are situated. It's a relatively safe place to stay too, especially for visitors to the country.
If you stay in the Makati hotels, you will also be quite near the big shopping malls, so it's very easy access to restaurants, night life and of course, shopping.
While Makati is a nice and comfortable area to stay in, your visit to Manila won't be complete unless you go out and explore the other cities and municipalities which are quite near each other within the Metropolitan Manila. The city of Manila for example offers a lot of our historical attractions and museums. San Juan, you'll find our famous bazaar shopping. Pasay, you'll find the largest mall and a place along the bay to see the sunset. And Taguig, you'll find a newly developed commercial area called The Fort for restaurants, nightlife, and shopping too. This used to be an old military base.
Enjoy your stay :-)