Siem Reap
Without question the best food in Siem Reap (and perhaps of your trip) is at the Hotel de la Paix, which is also a wonderful place to stay. Chef Paul Hutt is truly one of Asia's greats, making the very best of local ingredients and incredible presentation. Very nice room also.
While you are in Siem Reap, be sure to stop in at my brother-in-law's night spot, Linga Bar. It is the hot spot in town and most folks who get out at night seem to wind up there sooner or later.
Have fun.