One of such cool hangouts is Khao Sarn. Having lived 6 years in Bangkok, I'm very wary of Thai restaurants outside Thailand. Now this one I can recommend. If this was French outfit, it would be a brasserie: it churns out classic (some may say "same ole") Thai dishes consistent quality at reasonable prices.
We had a correctly cooked and served, with lime and green onions, phad Thai (somewhat on the smallish side) and the Isarn staple: grilled chicken leg with sticky rice and somtam (papaya salad).