Just returned. Here are some thoughts to share.
As hotels go, the St. Regis is not terribly expensive, is extremely convenient to the BTS, and has wonderful food, service, amenities. Great staff. Property is slightly dated in some common areas - pool and spa. Overall my though is that if it's within your budget it should be your first choice unless you are determined to be near the river.
Many people rave about the Sheraton Royal Orchid (it's a favorite on the flyertalk forums). We spent 2 nights there and it's OK but not great. Larger property. Close to the river and has nice ferry service but hard to get around because you usually have to take the ferry to the BTS stop then proceed on from there.
Grab is the Thai version of Uber. They used to have Uber. Not sure why they got rid of Uber. Grab is convenient and inexpensive. The drivers we used spoke no english or so little that it made things difficult. Don't count on communicating directly.
Google Translate is now useful for Thai. Previously when I had tried it lacked significant functionality vs German or French (for example). That appears to have been fixed.
I've spent probably 3 weeks in aggregate time in Bangkok. I think in the future I only need to go for 2-3 days and then go someplace else - either Chiang Mai or Laos for the next trip. Would like to see Ko Phi Phi also. This isn't because I don't love Bangkok. I do love Bangkok. It's just a big city and there are limited attractions. I like going primarily for good food and shopping at this point.
Lime soda (both home-made at restaurants and the stuff in 7-11's and Family Mart) is delicious and not sweet.
Check the Buddhist calendar as there are now days during the year (1-2 or even 3 day periods) where there are no alcohol sales anywhere but duty-free stores.
Also note (I could not find an answer on the web anywhere) - airport lounges (Thai Air in particular) DOES SERVE BOOZE during these holidays.
Crab yellow curry was my favorite dish this trip. I also continue to love Chiang Mai and Issan sausage.
Cooking schools seem to always offer the same few dishes (or minor variations) - glass noodle salad, some kind of curry, and fish cakes.
Raja's Fashions in Bangkok - make sure you go to the correct one (there's an imposter across the street) - is probably the only tailor I will ever use in the future. Made my 4th (I think) visit there. Lovely people. Lively shop with many returning customers. Reasonable prices. Lovely garments. Click the URL link and take note of what their logo looks like so you don't go to the wrong store.