A more powerful module than Data::HexDump, with various options to control output. And, as of today's version, as easy to use as Data::HexDump:
In the previous version, you had to write "hexdump(data => $data, [param1 => value1, ...])". I contacted the author requesting that the parameters hash be made optional, and he implemented this feature the next day, together with support for 64-bit data.
Excellent functionality, documentation, and support.