Although now with 5.10 you could do

while ( <DATA> ) {
  given( $_ ) {
    when ( $_ =~ /^NEW YORK:..../ ) {
      expression;
    }
    ...
    default {
       ...
    }
  }
}
[download]

Which is pretty nifty, imo

I personally believe that the most powerful characteristic of C<when>'s is the syntactic sugar it provides with implicit matches: which most of the times, actually happen to be smart matches - albeit not in this particular case, in which a similar beast that is a regular bind would be used anyway; thus you wouldn't do $_ =~ /REGEX/ but just as you wouldn't do in Perl quite about anywhere: because as usual you either want to use a full fledged generic variable and the binding operator, or the "topicalizer," i.e. $_, i.e. the pronoun "it" - but implicitly!