Speakers for a smaller room/moving issues...

I have Harbeth Monitor 20s (HL-P3es2 clones) in a 11 X 12 room.
Excellent. Low level dynamics are fine. Using a Naim Nait 5i.

BTW, here is a partial list of speakers I have tried in my above mentioned room with good results:

Monitors:
Joseph Audio RM7si
Neat Petites
PMC DB1+
Aerial 5
Linn Tukans
Audio Note Kspe
Dveore Fidelity Gibbon 3
Epos M5

Floor standers:
Totem Arros
Devore Fidelity Gibbon 8
Neat Elite
Spendor 5se

So you see, small rooms may be difficult, but not impossible.

I was once in your shoes, moving to NYC and wondering how this is going to affect my system. I have moved around quite a bit, but NYC is home now, so I've been able to stabilize my system and I think it is 'there'. In the past I have always been happy with 2 way monitor type speakers because they were easy to pack/ship and easy to integrate into any type of room. Do not feel bad about your 'listening room neurosis', you just understand what your priorities are, and your real estate agent should be made aware of it. Any good agent adapts to their customer's requirements, and believe me, here in NYC, they're grown ups and can handle most requirements of any kind (they see them all). If your current agent cannot handle your requirements, then get a new one?

But to get back to speaker recommendations, you are in the sweet spot because you have so much to choose from. I have settled in with the Wilson Duette speakers. I like these because of their resolution and frequency range. Their lower end is very very nicely rolled off just at the point where you would get yourself into trouble with your neighbors if they went any lower. They come 2 sets of jumper cables/resistors based upon how you want to set them up. Basically one set of wire is for an open room configuration where you have lots of space and your speakers are in the ideal configuration out from walls. The other set of wire is for non optimal setup, where your speakers are closer to boundaries - this is how I have mine setup. Basically the difference is sound is the 'close boundary' setup brings the presentation closer into the monitor, as if the entire stage has been pulled in closer to the speaker. Which really suits me because I am setup in the 'nearfield' listening mode due to a small listening room.

The Wilson Duette does demand a lot of your upstream gear however, so you have to be very cautious of equipment matching. The speaker will reveal any shortfalls in your wire, components, and setup.

The speaker is really quite flexible too, it has an outboard crossover so if you wanted to go with an active 2 way system, that is an option.

Properly setup, this speaker is very very good with small spaces. I think after living with the speaker for a while now, I have them optimally setup, and I'm very happy with the results.

I appreciate your replies so far. Good speaker recs plus--I feel somewhat less neurotic thanks to James. Normalization of my feelings-- a classic Dr. Phil move.
James, the Wilson audio speakers are out of my price range (heard great things though!) but it is not solely the bass I am worried about-- it's ALL of the frequencies!
I saw this beautiful condo the other day for example, with neighbors on either side of the living room (it's a middle unit). Good sized living room (bigger than my present room) and people who live there say they never hear their neighbors at all (it's a pricey place!).
Buuuut... once I start playing Aida one fine sunday morning-- all bets are off!?? And that goes for mini-monitors or maxi-monitors.
So even if the room is a good size and I use mini-monitors- I guess it's a crap shoot as to whether you are moving into a relatively noise-isolated environment. That worries me more than room size or speaker size right now. Is there any good way to know other than rapping on walls or being in the construction biz?
I can always change my speaker selection-- cant modify a rental condo/house's construction, though.

I think what you are concerned with will be a common theme in a densely populated area. In the city, I have people above, below, and on both sides of me so I have 4 sets of neighbors. I have a Radio Shack SPL meter I keep handy when I want to keep myself in check. But I have to say that I do listen to music at lower levels, on my SPL meter if I break 80db from where I am sitting, that is getting loud for my tastes. I have had no complaints from anyone the 7 years I've been here.

I live in a pre-war building, so you have to realize that my high rise building is made of concrete blocks and plaster, so it's very dense. You will find modern construction is pretty lousy as they always are cutting costs to maximize profits.

The issues I have is keeping the sound out from the street 6 floors below. I am fortunate that I live on a quiet street and not an busy avenue. But my building is plagued with a subway that runs under the building, which I can hear subtly. It is a very low frequency but it doesn't affect my sound too much in terms of component feedback. I keep my components very well isolated with vibration control devices.

Just some different points of view from my experiences.