What is the significance of the title of A Streetcar Named Desire?

The streetcar named "Desire" in the play was the one which
brought Blanche to the Kowalskis' shabby apartment in New Orleans.  Blanche even makes
reference to it upon her arrival (to the neighbour), even before Stella knows her sister
is there.

The ambulant streetcar
crisscrossing New Orleans represents Blanche's own vagrancy and her inability to settle
down. Blanche reproaches Stella for having married beneath
herself, but she has been unable to even do as much. Her husband Alan had killed himself
after a conjugal dispute. Then as a single schoolteacher, she also lost her job for
having made advances on a student. Later she loses the last vestiges of her reputation
hanging around a sleazy hotel as an easy "pickup."

Blanche
leaves her sister's place as abruptly as she came, only she does not leave alone nor
does she take cheap public transportation.  She is escorted to an insane asylum since
her stories of Stanley raping her (which are indeed true) are taken as a hysterical
fabulation.  Her last statement rings a certain truth, for she can no longer count on
friends, not even her sisiter Stella, and must rely on strangers for help. Her puerile
whims and unrestrained sexuality (her desires) have led her to to her own ruin, but so
has the incomprehension of others.

As far as changing the
title, "A Streetcar Named Desire" focuses much more on internal conflict than "A Poker
Night."  It is more general in scope and universal in theme; it evokes more pathos and
identification with the character as well.