In no particular order:
Cafe Rio - My fast food choice.Seriously great, fresh Mexican food.
Five/50 in Aria - not only do they have the best pizza in town, but some incredible salads, as well. My favorite dish is the meatballs - served with a spicy sauce, shaved parmesan, and toasted bread to sop up the sauce. Best part is, you can order from here while sitting at the poker tables, next door!
Bouchon - Best breakfast/brunch in town.
Bachi Burger - Japanese burgers with some of the best ground steak I've tasted.
Picasso - The best upscale restaurant in Vegas. The wine-tasting menu is still an experience.
Stack/Fix - Sister restaurants in the Mirage and Bellagio, respectively. Great, mid-priced comfort food. The very adult mac & cheese is to die for.
Lemongrass - My favorite Thai place. I try and get a hotter dish each time I'm there. I've gotten as far up the hot scale as a 7. I once tried to get a 10, and the chef came out and shook his head no. Too hot." One day!
Herbs & Rye - Great, classic Vegas dining with red booths, Italian fare, and a cool vibe.
SushiSamba - Best place to take visitors. So much fun - especially if you plunck down the $300-$600 it'll cost to get the Kobe Beef Hot Rock:
Vintner Grill
My favorite restaurant in Las Vegas. Hidden away in a non-descript office park off of Charleston, it's the most romantic, hippest off-strip place in town, with one of the best wine lists and sommeliers in town.
Jaleo - Fun, cool, and hip. My favorite tapas place.
Bartolotta - If you want to ask a girl to marry you, take her here. Amazing, upscale Italian in a fairy-tale setting.
SW Steakhouse - My favorite steakhouse in Vegas. Expensive, but worth it.
Sen of Japan - possibly the best sushi I've ever had. And it's not expensive!
The Barrymore - Old-time Vegas with a cool patio, a piano bar, and some of the best American cuisine on The Stip.
Nora's Cuisine - Family dining at its best.
Ferraro's - Maybe the most famous off-strip restaurant in Vegas - it's classic Italian menu is like going back to New York.
Todd's Unique Dining - how this isn't more popular, I have no idea. No one is doing more interesting and inexpensive fare than Todd.
Marche Bacchus - Lakeside dining with amazing food. What more could you ask for?
Milo's Cellar - Gotta give Boulder City some love - where else can you stop off on a drive to Lake Mead to get a bottle of wine, a baguette sandwich, and a cranberry-dressing salad, AND watch some sports on the TVs above?