Another vote for Mystere. Seen it multiple times and could continue to go as often as I get to Vegas!
I've stayed at Bally's more than anywhere else, but it's a ways off the street. Flamingo was nice (in updated rooms) and is smaller. Walk directly out the door onto the sidewalk.
You say you're not gamblers, but if you sign up for their player cards and play even a little, you will likely get offers for a return visit with discount room offers, packages, meal deals, etc. Cards and offers are good at other casinos in the group, too. MGM is part of such a hotel/casino group. Their web site will tell all of them. I've been offered three free nights at various places or amazing reduced rates at their higher end partners. Enjoy!