\@ is usefull if you need an array of arrays. eg:

my @x = (1, 2, 3, 4);
my @y = ();
[download]

and

push @y, \@x;
[download]

instead of

push @y, @x;
[download]

because the later will push the elements of @x onto @y, not @x itself. the same is true for \% of cause. to get the array out of the array of arrays again:

$z = pop @y;
@x = @{$z}; # or @$z
[download]

for more information on "strange" looking variables look at man perlvar and man perldata