Luxury Hotels - The Hamptons?

We're meeting some friends in NYC this summer for dinner and are considering adding a night in the Hamptons. I am familiar with the Reform Club (now Inn at Windmill Lane), Baker House 1650, and the Millhouse Inn.

Does anyone have feedback on these or other suggestions?

I'm not sure it makes sense for one night. Some properties have minimum stay requirements and the summer traffic can be awful, although of course a lot depends on the day of the week.

It would be a Sunday night.....which makes the one night stay more easily available. The traffic appears to be an issue once we get out there though since the 4th of July will be later that week.

On Monday, we would take the car ferries north to New England so would not need to go back to the city.