I have stayed at Hilton, which was fine for a conference, but rather far from anything useful.

If you are Starwood loyal, would recommend the Westin Banyan Tree (on Silom Rd), an all-suite hotel which I got through CX promotion for less than $100 per night for sure (although a few years ago). It has a Banyan Tree Spa on the 50th floor (or thereabouts), the suites are very tastefully decorated (lots of natural woods). A very relaxing place for a great city.

Recommend the Thai restaurant outside on the river bank lawn of the Shangri-La everytime. Call ahead and reserve a terrace table though.

Only thing to remember about BKK hotels is to carry plenty of their cards with maps and directions in Thai characters - for taxis/lost/police etc. Enjoy.