The Millenium Hilton is a great place to stay if you are having business to do in the Financial District of Manhattan. I like the hotel atmosphere and the location. The service is very friendly and the rooms are above average, both in style and size, compared to other hotels in New York.
Ask for a room above the 40th floor if possible and if possible not facing the large construction site on Ground 0. They work there basically 24h/7d and it can get pretty loud.

We booked two Grand Parlor Suites, I was given a room on the 54th floor and my family were in the 52nd, room 5210. Even though we paid the same price for both rooms, 5210 was much bigger than mine (5209). Both rooms had amazing views, were very clean and had lots of extras. The staff were extremely friendly and helpful, the concierge was brilliant and the staff in the gift shop couldn't do more to help.

It is in a great location, right next to Ground Zero in the downtown district. The subway is literally less than a 1 minute walk from the hotel which gets you to uptown in less than 5 mins.

My only gripe is that my massive widescreen TV didn't work in the lounge area, but there was another huge TV in the bedroom so I didn't bother contacting reception.

I highly recommend this hotel for anyone, if you are afraid of heights they do rooms on lower floors.

Paid $180 per night plus taxes on Priceline.
Hotel was as expected from other reviews. Pretty much all the rooms face Ground Zero and the construction which was kinda interesting to watch. Room was VERY spacious for any hotel standard forget NYC standards. My #906 was the lowest floor with rooms on it (I asked for this as I heard the wait for elevators was long on the upper floors and I wanted to be lower in case of an emergency). The construction did not bother me, the sound was little more than regular city noise you get anywhere. I did wake up once or twice around 6am cause I think they were moving some big piece of metal around or something, but fell right back asleep. I slept in til around 1030 one day & didnt use the earplugs or need to ask for the noise-reduction machine offered on checkin. There was some noise that came through from the corridor if there were people talking but that was rare as my impression was the hotel was far from full.
Had breakfast in the restaurant once, $$ but quite yummy (blueberry pancakes). They were pretty easy about doing substitutions if you wanted. There was also a buffet for $23.95 but it was quite small and no pancakes!
Bathroom was great, shampoos etc. were replaced daily. My only annoyance was somehow my phone would only ring in the bathroom, the cordless in the bedroom was connected to some other line which I could use to call out but no incoming calls. Free 800 calls were appreciated. You have to pay for internet use, not sure how much as I had my blackberry.
Employee service was excellent, fast checkin. I had some packages delivered and one of the security people worked very hard to locate them as they were initially missing. I also had a bit of a problem locking my door (my fault) and a security person was there within seconds. Someone also came right away to look at the phone issue, although they were not able to fix it and I didnt have time to bother calling again.
Accessibility was excellent with the E train being right outside and virtually all other subway lines within blocks. I also walked to the Brooklyn Bridge. Century 21 is right next door too. Cab from Laguardia cost about $30-40 depending on the route & direction as this hotel is further downtown that the midtown hotels.
I would recommend Woodbury Common Premium Outlets (you can drive there, about 1h, or take the bus from Port Authority $40 rtn which I did), much better deals than in Manhattan despite July 4 weekend sales.
I did not use the pool or any other amenities so cannot comment.

First of all, the top line of this review is that, while the hotel quotes its rates between $400 and $500, I was able to snag it for $175 on Priceline. And I'm sure people have gotten it for less before. Amazing deal at that price. At $500, I probably wouldn't have been as happy.

I think the reviews about the World Trade Center construction are exaggerated. I had a room facing ground zero and was not disrupted at all. If I turned off the TV and the air conditioner, I was only barely able to hear construction, but not at all if anything in the room was on.

The room had a 42" plasma TV which was nice, however there was no HD programming, which I find quite annoying. What's the purpose of having such a great TV if it has a crappy picture?

The bath linens and bed were very comfortable. I would have liked a few more outlets, though.