New Orleans. A charming city with great food, music, night life, and culture.
In light of the International info, check out the Azore Isles a fun (relative cheap) getaway.
The Portuguese islands of the Azores still give travelers the feeling of seeing something undiscovered. Here's how to go there now, before the secret gets out.
international, leaning towards leisure, non-mega city and overall affordable- maybe look into Belize for beach/forest vibes, Croatia for a European trip, or Curacao for an island vibe that is between the two. I confess I haven't been to the latter but it's on my list. I also hear Montenegro is a great destination!
I like @Woob_woob's suggestion and would throw out Mazatlan as well. within the US, central coast CA around Cayucos is always relaxed and lovely, and I think New Mexico as a destination is very overlooked.