if ($xml->is_simple() and $xml->is_table_like()) {
  use XML::RAX;

} elsif (size($xml) < too_big()) {
  use XML::Simple;

} else {
  use XML::Twig;
  ...
  my $Data = $DataObj->simplify(forcearray => [...], keyattr =>{ ... }
+, group_tags => {...});
}
[download]

Update 2007-2-6: Tastes change. While I would probably still use XML::RAX for some tasks with table-like XML and XML::Simple for very simple XMLs, I'd most probably use my XML::Rules now. May look a bit twisted at first, but it's convenient and powerfull. IMHO of course ;-)