The "second-best" thing I do regularly is to use path strings instead of building them with the File::Spec functions. It's all ActiveState's fault: their version of Perl for Win32 lets me get away with using open my $FH, '<', './data/source.txt' or die($!), where as other Win32 versions of Perl will not DWIM on the forward slashes.

This has bitten me more than once when one of the scripts I write for work gets run on a box using PXPerl...