Amsterdam Hotel

I enjoyed Hotel Keizershof more like B&B about 5blocks from train station.

Your best bet is the Avenue Hotel or the Ibis at Centraal Station. A bit more expensive, but the Golden Tulip Amsterdam Centre is an excellent hotel. Check www.booking.com they usually have the lowest rates for Amsterdam. If you're traveling off-season you can often get deeply discounted rates at the Grand Hotel Krasnapolsky (one of the top hotels in the city), for less than the Ibis.

We liked the Owl Hotel, reasonably priced and within walking distance of the museums.

I know you specified being near the Dam or Central Station, but if you haven't been to Amsterdam before, you might find the area depressing or somewhat off putting. Amsterdam is a small city, so even if I wanted to stay close to the station for convenience, I'd stay at a hotel located on one of the nearby canals. I can recommend the Wiechmann Hotel on the Prinsengracht canal. There are lots of nice places to eat around there & it's lovely to be on the canals.