In New York, the Park Views at Trump International Hotel are hard to beat. The Ritz-Carlton Central Park, the Taj Pierre, Sherry-Netherlands, and Mandarin-Oriental also have park views. However, perhaps only Trump will be within the OPs budget..... Leading Hotels of the World and the hotel site directly have specials.

For New York City views certain of the rooms at the Four Seasons and Waldorf Towers have great views. The Mandarin-Oriental seems to have great views also. However, I think these are also above the OPs budget. Perhaps an alternative would be the Millenium Hilton -- rooms higher up have some spectacular views....

In Hong Kong, I think the best views are from the Inter-Continental (former Regent) and a stay can be had here with the featured Harbourview at the OPs budget. Through Virtuoso, sometimes one can get a nicer room for the same price.