For your case I think 1 while s/// is as good as its going to get. Howver, if you wanted to match patterns that overlap the following code is fun to play with:

#!/usr/bin/perl -w
use strict;

$_ = '1ab2ab3ab4';
#     ^^^^
#        ^^^^
#           ^^^^
#  three substrings match /\dab\d/

my @nonoverlap = /\dab\d/g;    # this will only find two of them

my @overlap;
while (/(\dab\d)/g) {          # this will find all three
  push(@overlap,$1);
  pos($_) = $-[0] + 1;
}

print "nonoverlap: @nonoverlap\n";    # 1ab2 3ab4
print "overlap:    @overlap\n";       # 1ab2 2ab3 3ab4
[download]

The pos() assignment trick to find overlapping matches comes straight of out chapter 6 of japhys book which is probably the best /g documentation out there.

-Blake