$foo = (split/:/,$_,3)[1];

##</code><code>##

cchan.acsys.com.1.256% cat aaa3.pl 
use Benchmark; 
my $count = 1000000;
our $str = "a:b:c:d:e:ff:g:h:i:j:k:l:m:n:o:p:q:r:s:t:u:v:w:x:y:z";
timethese($count, {
          'slice' => sub { (undef, my $foo) = split /:/,$str; },
               'count' => sub { my $foo = (split/:/,$str,3)[1]; },
           });

##</code><code>##

Benchmark: timing 1000000 iterations of count, slice...
     count:  2 wallclock secs ( 3.18 usr +  0.01 sys =  3.19 CPU) @ 313479.62/s (n=1000000)
     slice:  3 wallclock secs ( 3.04 usr +  0.06 sys =  3.10 CPU) @ 322580.65/s (n=1000000)