Based partially on btrott's answer (above), I wanted to provide a solution
which would keep the table balanced (i.e. put 3 td's on each row - even if
the last row wouldn't otherwise be full).

I've basically become anal about uninitialized value warnings, so if you
don't care about them, you can ditch the ternary operators...

my %subcat = (Foo => 3, Bar => 2, Baz => 10, Quux => 1);
my @Keys = keys %subcat;
while (my $Temp = [splice @Keys, 0, 3]){
  print "<tr>\n";
  print defined @$Temp[0] ? "  <td>@$Temp[0] ($subcat{@$Temp[0]})</td>
+\n"
                          : "  <td></td>\n";
  print defined @$Temp[1] ? "  <td>@$Temp[1] ($subcat{@$Temp[1]})</td>
+\n"
                          : "  <td></td>\n";
  print defined @$Temp[2] ? "  <td>@$Temp[2] ($subcat{@$Temp[2]})</td>
+\n"
                          : "  <td></td>\n";
  print "</tr>\n";
  last unless @Keys;
}
[download]

A note about the code: I opted here to simply print three lines rather than
use an inner for (0..2) loop. The net cost is two lines of code, but it
made the purpose of that section of code very obvious. I consider it worth
the cost...

Russ