Whenever in Vegas and staying anywhere near downtown, I always visit La Thai! Everything I have tried is very good, however what I always crave and have to order is the Tom Kha soup which is awesome! You know from the moment it arrives your in for a treat as the smell wafting up from the bowl is amazing, it tickles the senses! Then you dive in and experience an explosion of different flavors. In each spoonful you get a exotic mixture of coconut, fresh mushrooms lemon, cilantro, spring onions,ginger, and Thai spice. Also if you ask they will gladly add rice noodles to the soup which I definitely recommend.
The place is not large and so on the weekend there is usually a little wait. However during the week have never had any wait. Also they have a take out window were you can order to go. They also have a small patio with 5 were you can sit outside and watch the flow on Fremont street which is always interesting! In addition the service each time I have visited has been very good and always friendly.
My only word of advice when you order they ask how spicy you want it. They offer from 0 (no spice) to 5 (Thai spice), with 3 listed as hot. Well this rating scale is accurate! I have found most places embellish so if 3 says hot, well it is usually not really that hot. Howeveri I have ordered a 3 at La Thai and it was definitely hot!