Go and read Death to Dot Star! >;->
The problem is that your regex, while not greedy, still matches as early as possible, causing it to match things like 'stuff</td><td>email@email.com'. If you replace the dots with a negated character classes, preventing them from matching the angle brackets of the <td> tags, then it should work perfectly:

#!/usr/bin/perl -w

use strict;

my $data = 'any number of td/tds><td>stuff</td><td>email@email.com</td
+><td>more stfff</td><td>next@next.co.uk</td><td\>r.h@a.com</td>';

my @emails = ($data =~ /<td>([^>\@]+?\@[^<\@]+)<\/td>/g);

print join "\n", @emails;
[download]

However, this is definitely a job for Email::Find:

#!/usr/bin/perl -w

use strict;
use Email::Find;

my $data = 'any number of td/tds><td>stuff</td><td>email@email.com</td
+><td>more stfff</td><td>next@next.co.uk</td><td\>r.h@a.com</td>';

find_emails($data, sub {
    my($email, $orig_email) = @_;
    print $email->format."\n";
    return $orig_email;
});
[download]