Looking for someplace to stay next xmas -- 40-somethings, no kids, want relaxing, quiet, pleasant pool area, walk-to location, pretty room. Suggestions?

You will probably want to stick to a Bed and Breakfast as most do not allow children. I suggest the Marquesa. We stayed there a couple of times and its very luxurious and has a great location. I think its 4 diamond rated.

How about something that won't break the bank -- $200 per night or less?

You probably wont find exactly what you are looking for during that time for you budget. Christmas week is the busiest time there so all places get sky high rates - even the low end motels. I am not even sure Priceline would work for that week. If you really want something relaxing maybe you would think about staying on one of the other Keys or traveling to Key West during a different time of year. We have gone in the beginning of Dec and had luck with decent rates and things not being so conjested and crazed with cruise ship tourist.

I would recommend the Key West Harbor Inn. It is a large inn, serves a continental breakfast, and has a cocktail hour late afternoon. The pool is small, but quiet, and has a nice hottub as well, that is a bit secluded. The rooms are clean and attractively decorated. We had a queen bed room, private bath, with a small fridge. Each room is named after an island in the Carribean. It is very near the marina area, and just a few blocks from Duvall Street. I found the neighborhood to be very quiet, even though it is close to the main areas.

For a more budget option, look at Merlin Guesthouse. It has a wide variety of room types, I'd probably avoid the cheapest, I've heard they can be noisy. But, it's cheaper than many other spots and the pool area was pleasant. Ok breakfast.

Which of the other Keys would you recommend? Do any of them have nice sandy beaches?

No nice sandy beaches in the keys except for Bahia Honda and it is a state park. Most sand is brought into the keys by barge from the Bahamas.

The Wyndham has a decent beach and great pool and staying at one, you can use the facilities at the Reach and Casa Marina but not sure if they'll be in your price range. That is peak season for the keys.

Check out the Southernmost Hotel.

The Heron House has a nice pool area and is slightly cheaper than the Marquesa. We also stay in Key Largo (on the Bay side) & there are some nice little beaches there. Bahai Honda does have the nicest beaches & clearest water. If you can move your dates back prior to Dec. 15th you may have better luck, price-wise. Thanksgiving is a great time to be in the Keys.

Bahia Honda is gorgeous and around mile marker 35 I think so maybe you could find something near it but it wont have near the activities Key West has. We stayed at Hampton Inn in Islamorada a few years back and it was nice but aain not much to do.......husband fished and we hung out around the pool.
Last I heard, the Wyndhams have been going through a lot of changes and renovations since the sale. Especially the Casa, they even closed down the indoor bar and restaurant.

Take a look at the website for Chelsea House in KW... nice pool area, good location, decent rates, and nice rooms. We stayed there and found it to be a great example of the KW experience.

I've posted a link to the Ambrosia. We were supposed to go this spring and were looking for the same kind of place. We met some folks who stayed at the Ambrosia and LOVED it. If we hadn't had to change our plans, we definitely would have stayed there.

http://ambrosiakeywest.com

Well, we have to go between xmas and New Year's. Believe me, I wish it were otherwise. I chose Key West because it a) looks appealing, and b) figured we will be almost guaranteed warm temperatures. We will fly into Miami, so now I am wondering if there's perhaps another place in south Florida where we can expect warm weather and enjoy the beaches. I know there's no guarantee, but from what I've been reading, the average temps in the K
eys are pretty balmy.

If you want great beaches and warm weather, either stay in Miami Beach or drive over to Naples.

Or in the alternative, Fort Lauderdale.
The Pelican Beach Resort -www.pelicanbeach.com is right on the beach and is gorgeous. Ft. Lauderdale is less hectic than Miami and has better beaches...in my opinion