A place that we tried out the last time we were there in August was Lotus of Siam which was a thai place that was also featured by Anthony Bourdain: Parts Unknown in Las Vegas.
It's north of the strip a bit so you'll need to use a car to get there or I guess transit or cab. It's not the nicest area but just use common sense and things should be fine (when you walk into the restaurant, a sign warns you to keep all your valuables out of sight in your car due to lots of breakins)
Place is always busy so I'd recommend you make a reservation, when we got there, the waiting room was packed and the place (which was larger than it appeared from the outside) was packed
If you haven't seen the episode I was speaking about before, you should watch it, TL-DR version pretty much is, this is one of the best thai places in the states and order from the northern section of the menu as this is their speciality, order something like pad thai and Anthony Bourdain will personally punch you in the face :P
I'm probably heading down there again in December so any tips on food places off the beaten path would be great