In June 2017 I was for 1 night at a hotel on Soi 20 of Sukhumvit and this hotel does not serve breakfast. So where to go for breakfast? I did choose the breakfast buffet of Well Hotel on Sukhumvit soi 20. They serve a big buffet with European, Thai, Chinese and Japanese food. And fresh made tea or coffee. Personally I love the bread section with home made bread and home made jam. Besides the good food the staff is super friendly. And at about 550 Thai baht pp I think it is for Sukhumvit standards not expensive (but I think prices of restaurants at Sukhumvit have become ridicules expensive). If you like some help with organizing your holiday anywhere in Thailand send me an email at The Little Elephant Traveling in Thailand.
Disclaimer : All information is created in good faith and is an expression of fair comment.