Thanks for mentioning the site, I'll certainly check out their rates the next time I plan a trip to NYC. As to hotel tips, I prefer a mid-town location and have stayed at the Doubletree a few times. It's smack in the middle of Times Square and all rooms are suites with a seperate bedroom and a living room equipped with a large fridge, a coffee-maker, micro-wave etc. The interior is functional and particularly elegant but it's nice to have almost a little apartment for longer stays.
Last time I was in NY the rates the Doubletree showed were very high so I booked a room at the Barclay Intercontinental on East 48th. It's a very nice hotel with a good if not perfect location, the rooms are fit with everything one could need, are well maintained and pleasantly furnished. Rates generally seem to have been lowered since I visited the last time, the weekend rate for the Barclay is around 160 USD and 200 during the week, I paid almost 30% more last November.
If you need a room in Europe, I can highly recommend the site www.hrs.de . You enter the dates and city and it shows only free rooms, almost always with the best rate available. You book directly into the hotel's reservation system and get your confirmation code by email, it's very reliable and you can find rooms even for small towns.