(RESULTS)
Elements:17576
sub took:  52 (51.14 usr +  0.00 sys = 51.14 CPU)
scan took: 17 (13.85 usr +  0.00 sys = 13.85 CPU)
hash took:  0 ( 0.17 usr +  0.13 sys =  0.30 CPU)

(CODE)
#!/usr/bin/perl -w

use Benchmark;

@List = ("aaa" .. "zzz");
print "Elements:", scalar @List, "\n";

@rand_list = map $List[rand @List], 1 .. 100;

sub first (&@) {
  my $cref = shift;
  $cref->($_) and return $_ for @_;
}

$t0 = new Benchmark;
for (@rand_list) {
  $rand_element = $_;
  $first_match = first {$_ eq $rand_element } @List;
}
$t1 = new Benchmark;
$td = timediff($t1, $t0);
print "sub took: ", timestr($td), "\n";


$t0 = new Benchmark;
for (@rand_list) {
  $rand_element = $_;
  for (@List) { last if $_ eq $rand_element }
}
$t1 = new Benchmark;
$td = timediff($t1, $t0);
print "scan took: ", timestr($td), "\n";



$t0 = new Benchmark;
my %seen;
@seen{@List} = ();
$t1 = new Benchmark;
$td = timediff($t1, $t0);
for (@rand_list) { 1 if exists $seen{$_} }
print "hash took: ", timestr($td), "\n";