Yes, belligerentyouth, was right, Up town is where the money is..
As to whether it is always UP-- it's hard to tell NY's uptown, is just North --actually its mid manhattan island.
the upper east side of manhattan has so much wealth-- it made a real "blip" on the census map-- a 1 mile, by 1/2 mile strip, Fifth Ave to Lexington from 60th to 80th street, mostly apartment buildings, so fairly high density, had average family income over $1.5 million. Down town, still included the "lower east side" -- an area of low income,-- the same area featured in the 1930's movies, "the Bowery boys". Alphabet city -- an area in manhatten that has Avenues with letter names, Ave A, Ave B, etc., was the site of the first planned public housing in US--Jacob Riis's plan.

though, now parts of NY's Downtown have become trendy, and more expensive, (TriBeca, or Dumbo) they are still reletively cheap compared to the upper east side.

DUMBO=Down Under Manhattan Bridge Overpass, TriBeca=Triangle Below Canal, SoHo=South of Houston.