The city of Las Vegas is a real jumble; it's not uncommon to have middle class single family homes next to Section 8 housing next to huge luxury estates next to commercial areas. So the newer "good neighborhoods," like the aforementioned Summerlin, Henderson, and Lake Las Vegas are a more homogeneous choice.
If by good neighborhood you mean low crime, there are any number of crime maps available at the touch of a Google. If good means good schools, move to a different state that actually gives a shit about children. If a good neighborhood means nearby medical care, may I suggest living near the airport. It's where locals go for quality medical care.
And if you're adventurous, hip, fearless - and therefore probably young - Fremont East is gradually being transformed by the Downtown Project and a couple of hundred million dollars from Tony Hsei. As far as I'm concerned, walkable neighborhoods like that really are the coolest places to live, and unwalkable, car-centric 'burbs lead to boredom, isolation, and excessive television watching. That's not good.
