Given the current large scale renovations going on at the Four Seasons, when complete, will offer, IMHO, Bangkok's best rooms. You can see a sample of the newly renovated rooms at the Four Seasons Bangkok website -- click on Deluxe room. It has a modern Thai flair, large plasma screen, and still the best and most comprehensive service thus far in any hotel I have stayed at in Bangkok.

The Oriental and Peninsula didn't know what a humidifier was when I asked for one (having one is preferable for medical reasons); the Four Seasons' response was, "right away!!"

However, the Peninsula does offer a fantastic value and perhaps that is its main strength. But with the Four Seasons renovations currently underway and with their service levels, for me, I still vote the Four Seasons as the best hotel in Bangkok. Will be interesting to see how the forthcoming Regent will turn out....