Obviously all the casino & gambling stuff.
I like the Vegas weather, at least when it's hot out. I can't stand this bullshit cold winter time, it's awful.
It's nice that stuff is actually open late or 24/7. Outside of LV, lots of stuff is closed by 8 or 10pm it seems.
Easy to fly in/out of LV. Like Druff said, people are going to visit LV anyway because it's a tourist destination and lots of conferences or w/e here so people come for work. Just about everywhere I've flown to has a direct flight from LV, so don't have to do connecting flights.
Restaurants are great, especially since they're pretty much all attached to a casino, not hard to get comps. Also easy to get comps for friends and family for hotel rooms. Although this is probably more due to AP than just living in LV.
Lots of shows (although I'm not a huge fan), but supposedly they're world class.
I have excellent Internet where I live which is nice because I enjoy streaming Netflix, YouTube videos, and playing an online video game. Where I've lived in the past, the Internet was absolutely atrocious, it was super slow and would cut out a lot. I guess that's not particularly dependent on being in LV, since the neighborhood over could have terrible Internet. I just clocked it at 267Mbps download and 32Mbps upload.
Vegas seems pretty relaxed to me. Maybe it's just me in my aging years, but seems like when/where I was growing up, there was a lot more drama and bullshit with people. Obviously there are other places like in the South or the Midwest(?) where there's even a more relaxed atmosphere. I think I'd hate to live in the Northeast....or at least that's a stereotype they have, right?