grep is probably best here, as meowchow said. But now that I've said that, I think if you just decrement the index before doing the next you're code will do what you expect. Here's my snippet:

use strict;
use warnings;

my @arry = qw ( 1 5 5 5 5 2 );
my $i = 0;

print "@arry\n";

for ($i = 0; $i < @arry; $i++) {
    next unless $arry[$i] == 5;
    splice (@arry, $i, 1);
    --$i;
}

print "@arry\n";
[download]

I personally think this is ugly and more difficult to follow than:

use strict;
use warnings;

my @arry = qw ( 1 5 5 5 5 2 );
my $i = 0;

print "@arry\n";

@arry = grep { $_ != 5 } @arry;

print "@arry\n";
[download]

but maybe that's just me.

Ira,

"So... What do all these little arrows mean?"
~unknown