OK, first of all some basic tips before going to Amsterdam:
Bookings.nl. In some cases, it offers 50% cheaper rates than I got from three different Czech travel agencies! Also, when we arrived and the hotel desk, they checked if we really want non-smoking room (without asking what stuff specifically we will not smoke) and when we confirmed this fact, we got a free room upgrade. In the end, for 500 Euro, we got five nights in rather excellent room which normally costs 290 - 350 Euros per night.
As for the location, it's probably best to stay in a hotel near the "Dam Square". From our five-day experience, this neighborhood is the only public place that feels both alive and safe even late in the evening. It's rather weird but even shops in the heart of the city open rather late (after noon!) and close rather soon (at 6 PM!), even two weeks before Christmas! Of course, if you'd rather spend the evening in the pub or night clubs, you can fulfill your desires in almost any part of the city.