Dave Aitel, CTO of Immunity has released their new debugger which was built using Python. It boasts the industries first heap analysis tool, and "analyze malware,
and reverse engineer binary files". I have not had a chance to play with it yet, but I’m fairly certain it will be quite good. On that note, many thanks to Dave Aitel and company for donating a ton of billable hours in order to develop Immunity Debugger and then release it for free.