Archi's on Sahara serves up very solid Thai food. I live very close to this location and order takeout frequently, but I have eaten in the restaurant many times as well - I recommend both!
My favorite things on the menu are the pad see ew and tom kha ghai (chicken coconut soup). I love the broth so much that I usually order extra broth and less of the soup contents. Once it didn't work out so well - I got home to find that they had written "extra broc" on the top of the soup container and the entire soup was filled with broccoli! :) Even though it wasn't what I wanted, it still scores them a point for doing anything a customer asks, even when broccoli isn't actually an ingredient in the soup!!
The curries, salads, and other appetizers are quite good too (except I've never been a huge fan of the spring rolls, which are normally my favorite thing at a thai place). Prices are very reasonable and everyone is friendly. Not the best thai in Las Vegas, but good enough to keep going back!