Lunchcounter at Foodland, Sukhumvit Soi 5 (opposite Amari Boulevard hotel)
This is open 24 hours and has just about everything; Thai, western. They have an American breakfast for 41 baht, until 9:00 AM. Excellent, inexpensive fare.

Pizza, Bella Napoli, Sukhumvit Soi 33 (halfway down, opposite Monet club)
Good pizza.

The Food Center (6th floor) at Mah Boon Krong (MBK) shopping center (National Stadium stop on the BTS). This is a big food court, maybe ~ 40 “stalls”. You buy coupons in 20/10/5 baht denominations at booths near the entrances, and use these to buy food/drinks at the various stalls. You redeem unused coupons before you leave. Typical dishes are 30/35 baht. Go to the stall with the longest line!

I mostly ate street food this week, great hamburger from a cart on the right of the entrance to NEP on Sukhumvit Soi 4, excellent satay from a barbeque cart just to the left of the entrance to NEP. Great Issan (barbequed pork, spicy salad, etc.) food from a cart down Soi 4 on the right, just opposite Soi 6. The sheer number of street food vendors in BKK is staggering. The same spot on a street might have three different vendors throughout the day.