Japanese - sushi is still best in Japan, still miss that
Guu Izakaya - very popular, either show up early or late or you'll have to wait, fun atmosphere
Ematei - their cooked food is quite good, sushi is decent
Solo Sushi Bekkan - sushi was good, quite fresh
Mengrai Gourmet Thai
Hanoi 3 Seasons (Northern Vietnamese style)
I've been rather disappointed with the Chinese food downtown, nothing really has stood out. Korean, I can't remember the names of the restaurants I like, just the locations.